Implemented arguments processor.
Use cmdargs for command line parsing.
Used case-of pattern matching to improve safety.

Improved debug print statements.
Merge branch cmdargs into feature/argumentsProcessor

Removed Setup.hs for now.
Switched to lower case convention for diffr.cabal.
Switched to single binary.
Parses arguments for diff, closes #6
Parses arguments for patch, closes #7
Merged pull requests, closes #8, closes #9