Improved ERC721 granularity (#1304)

* Split enumerable and metadata implementations.

* Renamed ERC721Basic to ERC721, and ERC721 to ERC721Full.

* Fixed linter errors.

Author: nventuro

contracts/mocks/ERC721BasicMock.sol

@@ -0,0 +1,30 @@
+pragma solidity ^0.4.24;
+
+import "../token/ERC721/ERC721Full.sol";
+import "../token/ERC721/ERC721Mintable.sol";
+import "../token/ERC721/ERC721Burnable.sol";
+
+
+/**
+ * @title ERC721Mock
+ * This mock just provides a public mint and burn functions for testing purposes,
+ * and a public setter for metadata URI
+ */
+contract ERC721FullMock is ERC721Full, ERC721Mintable, ERC721Burnable {
+  constructor(string name, string symbol) public
+    ERC721Mintable()
+    ERC721Full(name, symbol)
+  {}
+
+  function exists(uint256 tokenId) public view returns (bool) {
+    return _exists(tokenId);
+  }
+
+  function setTokenURI(uint256 tokenId, string uri) public {
+    _setTokenURI(tokenId, uri);
+  }
+
+  function removeTokenFrom(address from, uint256 tokenId) public {
+    _removeTokenFrom(from, tokenId);
+  }
+}

contracts/mocks/ERC721FullMock.sol

@@ -1,17 +1,19 @@
 pragma solidity ^0.4.24;
 
-import "../token/ERC721/ERC721.sol";
+import "../token/ERC721/ERC721Full.sol";
 import "../token/ERC721/ERC721Mintable.sol";
 import "../token/ERC721/ERC721Burnable.sol";
 
 
 /**
  * @title ERC721MintableBurnableImpl
  */
-contract ERC721MintableBurnableImpl is ERC721, ERC721Mintable, ERC721Burnable {
+contract ERC721MintableBurnableImpl
+  is ERC721Full, ERC721Mintable, ERC721Burnable {
+
   constructor()
     ERC721Mintable()
-    ERC721("Test", "TEST")
+    ERC721Full("Test", "TEST")
     public
   {
   }

contracts/mocks/ERC721MintableBurnableImpl.sol

@@ -1,30 +1,18 @@
 pragma solidity ^0.4.24;
 
 import "../token/ERC721/ERC721.sol";
-import "../token/ERC721/ERC721Mintable.sol";
-import "../token/ERC721/ERC721Burnable.sol";
 
 
 /**
  * @title ERC721Mock
- * This mock just provides a public mint and burn functions for testing purposes,
- * and a public setter for metadata URI
+ * This mock just provides a public mint and burn functions for testing purposes
  */
-contract ERC721Mock is ERC721, ERC721Mintable, ERC721Burnable {
-  constructor(string name, string symbol) public
-    ERC721Mintable()
-    ERC721(name, symbol)
-  {}
-
-  function exists(uint256 tokenId) public view returns (bool) {
-    return _exists(tokenId);
-  }
-
-  function setTokenURI(uint256 tokenId, string uri) public {
-    _setTokenURI(tokenId, uri);
+contract ERC721Mock is ERC721 {
+  function mint(address to, uint256 tokenId) public {
+    _mint(to, tokenId);
   }
 
-  function removeTokenFrom(address from, uint256 tokenId) public {
-    _removeTokenFrom(from, tokenId);
+  function burn(uint256 tokenId) public {
+    _burn(ownerOf(tokenId), tokenId);
   }
 }