Fix typo in initial config

Capitalization mismatch between initial config and the setting that is read causes the path to the flake8 executable to never be picked up
Add options: max line length, ignore error codes

Added option to specify maximum line length and ignore specified error codes
Set defaults for maxLineLength, ignoreErrorCodes

Specified a default max line length of 79 chars (PEP8 default) and report all error codes by default
Merge pull request #3 from bstrdsmkr/pass-options

Add options, fix typo in defaults