ohcount: License Documentation

# License Documentation

Author:
  Mitchell Foral

## How to Add a New License

- Add your license to 'src/licenses.h' and 'src/licenses.c'. Don't forget that two '\'s are required to represent one '\' in a C string.
- Add your tests to the 'test/src_licenses/' and 'test/expected_licenses/' directories. Note that multiple licenses must be separated by newlines and be in the order they appear in the input file.
- Run the test suite (a rebuild is not necessary; your added tests are detected and run automatically) to verify your licenses are correctly detected.
- Rebuild Ohcount.