Added support for relative file paths
- App now accepts '-f /c/users/someGuy/desktop/file.groovy' or '-f file.groovy' (long as g2exe resides in /c/users/someGuy/desktop/)
- Refactored some code to improve readability (OptionAccessor was confusing, so I aliased it to 'Input' to try and be more obvious)
- Removed unused validation check from OptionAccessorValidator