Initial spike of processor required for incremental compilation of C++
Regex-backed implementation of source dependency parser

- Ignores files that are not located in provided path, so system headers will not participate in incremental compile determination
Added test demonstrating issue with incremental build and C++ header files
Use hash to check if files have changed, rather than comparing text
Refactored C++ incremental build integration test to make it more amenable to testing incremental compile
Checkstyle fixes