Use prefix underscore for state variables and no underscore for parameters

CODE_STYLE.md

@@ -16,35 +16,19 @@ Any exception or additions specific to our project are documented below.
 
 * Try to avoid acronyms and abbreviations.
 
-* Parameters must be prefixed with an underscore.
-
-    ```
-    function test(uint256 _testParameter1, uint256 _testParameter2) {
-    ...
-    }
-    ```
-
-  The exception are the parameters of events. There is no chance of ambiguity
-  with these, so they should not have underscores. Not even if they are
-  specified on an ERC with underscores; removing them doesn't change the ABI,
-  so we should be consistent with the rest of the events in this repository
-  and remove them.
-
-* Internal and private state variables should have an underscore suffix.
+* Private state variables should have an underscore prefix.
 
     ```
     contract TestContract {
-      uint256 internal internalVar_;
-      uint256 private privateVar_;
+      uint256 private _privateVar;
     }
     ```
 
-  Variables declared in a function should not follow this rule.
+* Parameters must not be prefixed with an underscore.
 
     ```
-    function test() {
-      uint256 functionVar;
-      ...
+    function test(uint256 testParameter1, uint256 testParameter2) {
+    ...
     }
     ```
 

contracts/access/roles/CapperRole.sol

@@ -20,21 +20,21 @@ contract CapperRole {
     _;
   }
 
-  function isCapper(address _account) public view returns (bool) {
-    return cappers.has(_account);
+  function isCapper(address account) public view returns (bool) {
+    return cappers.has(account);
   }
 
-  function addCapper(address _account) public onlyCapper {
-    cappers.add(_account);
-    emit CapperAdded(_account);
+  function addCapper(address account) public onlyCapper {
+    cappers.add(account);
+    emit CapperAdded(account);
   }
 
   function renounceCapper() public {
     cappers.remove(msg.sender);
   }
 
-  function _removeCapper(address _account) internal {
-    cappers.remove(_account);
-    emit CapperRemoved(_account);
+  function _removeCapper(address account) internal {
+    cappers.remove(account);
+    emit CapperRemoved(account);
   }
 }

contracts/access/roles/MinterRole.sol

@@ -20,21 +20,21 @@ contract MinterRole {
     _;
   }
 
-  function isMinter(address _account) public view returns (bool) {
-    return minters.has(_account);
+  function isMinter(address account) public view returns (bool) {
+    return minters.has(account);
   }
 
-  function addMinter(address _account) public onlyMinter {
-    minters.add(_account);
-    emit MinterAdded(_account);
+  function addMinter(address account) public onlyMinter {
+    minters.add(account);
+    emit MinterAdded(account);
   }
 
   function renounceMinter() public {
     minters.remove(msg.sender);
   }
 
-  function _removeMinter(address _account) internal {
-    minters.remove(_account);
-    emit MinterRemoved(_account);
+  function _removeMinter(address account) internal {
+    minters.remove(account);
+    emit MinterRemoved(account);
   }
 }

contracts/access/roles/PauserRole.sol

@@ -20,21 +20,21 @@ contract PauserRole {
     _;
   }
 
-  function isPauser(address _account) public view returns (bool) {
-    return pausers.has(_account);
+  function isPauser(address account) public view returns (bool) {
+    return pausers.has(account);
   }
 
-  function addPauser(address _account) public onlyPauser {
-    pausers.add(_account);
-    emit PauserAdded(_account);
+  function addPauser(address account) public onlyPauser {
+    pausers.add(account);
+    emit PauserAdded(account);
   }
 
   function renouncePauser() public {
     pausers.remove(msg.sender);
   }
 
-  function _removePauser(address _account) internal {
-    pausers.remove(_account);
-    emit PauserRemoved(_account);
+  function _removePauser(address account) internal {
+    pausers.remove(account);
+    emit PauserRemoved(account);
   }
 }

contracts/access/roles/SignerRole.sol

@@ -20,21 +20,21 @@ contract SignerRole {
     _;
   }
 
-  function isSigner(address _account) public view returns (bool) {
-    return signers.has(_account);
+  function isSigner(address account) public view returns (bool) {
+    return signers.has(account);
   }
 
-  function addSigner(address _account) public onlySigner {
-    signers.add(_account);
-    emit SignerAdded(_account);
+  function addSigner(address account) public onlySigner {
+    signers.add(account);
+    emit SignerAdded(account);
   }
 
   function renounceSigner() public {
     signers.remove(msg.sender);
   }
 
-  function _removeSigner(address _account) internal {
-    signers.remove(_account);
-    emit SignerRemoved(_account);
+  function _removeSigner(address account) internal {
+    signers.remove(account);
+    emit SignerRemoved(account);
   }
 }

contracts/bounties/BreakInvariantBounty.sol

@@ -10,24 +10,24 @@ import "../ownership/Ownable.sol";
  * @dev This bounty will pay out to a researcher if they break invariant logic of the contract.
  */
 contract BreakInvariantBounty is PullPayment, Ownable {
-  bool private claimed_;
-  mapping(address => address) private researchers;
+  bool private _claimed;
+  mapping(address => address) private _researchers;
 
   event TargetCreated(address createdAddress);
 
   /**
    * @dev Fallback function allowing the contract to receive funds, if they haven't already been claimed.
    */
   function() external payable {
-    require(!claimed_);
+    require(!_claimed);
   }
 
   /**
    * @dev Determine if the bounty was claimed.
    * @return true if the bounty was claimed, false otherwise.
    */
   function claimed() public view returns(bool) {
-    return claimed_;
+    return _claimed;
   }
 
   /**
@@ -37,22 +37,22 @@ contract BreakInvariantBounty is PullPayment, Ownable {
    */
   function createTarget() public returns(Target) {
     Target target = Target(_deployContract());
-    researchers[target] = msg.sender;
+    _researchers[target] = msg.sender;
     emit TargetCreated(target);
     return target;
   }
 
   /**
    * @dev Transfers the contract funds to the researcher that proved the contract is broken.
-   * @param _target contract
+   * @param target contract
    */
-  function claim(Target _target) public {
-    address researcher = researchers[_target];
+  function claim(Target target) public {
+    address researcher = _researchers[target];
     require(researcher != address(0));
     // Check Target contract invariants
-    require(!_target.checkInvariant());
+    require(!target.checkInvariant());
     _asyncTransfer(researcher, address(this).balance);
-    claimed_ = true;
+    _claimed = true;
   }
 
   /**