get things compiling again with gcc

fixes compilation and linkage issues with gcc
- due to use of c++11-only features (in this case, to_wstring), compilation requires -std=gnu++11
- some static const ints were optimized out of a header file and were causing linkage issues; moved them to corresponding .cpp file
- modified .gitignore slightly to allow for symlinks to original xcom data instead of real directories (real directories still work, of course)