Merge pull request #1 from okin/refactor

Refactoring
Update satprep_snapshot.py

Fixed issues #5 and #6
Update satprep_snapshot.py

Cleaned code (a little bit :p)
Consistent indentation with only tabs.

Python 3 will break with mixed indent.
Moving the parsing of options and the main part into seperate functions.
Another indentation fix.
Reworked the option parsing.
Using a logger.
Added shared lib to have less duplicate code.
Ingoring .pyc and .pyo-files.
Using SUPPORTED_API_LEVELS from shared lib.
Reorder imports.
Added Exception for showing that the API level is not supported.
Using that new exception instead of just sys.exit-ing
Fix re-login part.
Optional args parameter filled.
Check for supported api level in shared lib.
Moving the processing of systems into functions.
Reworked process_erratas
Refactored process_patches.