Merge pull request #1 from cym13/master

Implemented exceptions
Prepare for module
Finish modularization
Package is now in pypi
Move range selection for time selection in a function
Move defines in private attributes
Use a fixed model for event parsing
Change in the API in answer to issue #2

Restores Extranet(...).get_timetable() use,
also the old `days' optionnal argument can be used if specified explicitely.
This should be deprecated though.