0.6.1

Fixed an issue with parsing C++ header files after I noticed something was off w/ livegrep on the demo site: https://codebased.sh.
For better or for worse, C header files are parsed as C++ header files now.
This should work because C++ is a syntactic superset of C (say that five times fast).
In turn, our C++ parser extends the C parser now.
This uncovered a bug in how C-style constructs were parsed in C++.
All in all, this change fixes a few bugs and enhances the parser's test coverage.