MAINT: Cleanup pandas/src/parser
Remove dead code and reformat for style using Google's C++ style guide (found <a href="https://google.github.io/styleguide/cppguide.html">here</a>).

Also adds line of code to install fork of Google's C++ style checker (source code <a href="https://github.com/cpplint/cpplint">here</a>) when doing style checks in Travis.