Some refactoring for PEP8, better naming and future testability

- Changed the command line arguments to just use a file without needing a flag
- Refactored MapConfig to MapFile (it's not a configuration file)
- Moved some methods to be functions (no reason for them being methods)
- Renamed some variables to be PEP8 compliant
- Added docstrings
- Fixed up a few properties to be more fault tolerant
- Added some more points of interest in the example file
- Updated README.md for new way to call minemap