Moved common methods into base class.

Parsing seats and date is common in every subclass, a little bit cleaner.
Small refactorings
Added PKR hands and one test. Modified common attribute descriptions.
Fixed wrong tests
Implemented PKR parser fully. First test passing.
Merge branch 'pkr_parser'
One dictionary with set lookups
Refactored dictionary lookups to function calls.

One normalize function for all values!
Merge branch 'normalize'
Bumped version number, updated README