Deleting FirstStageBaseEventClass.

The class was merged with DetailedLogWriterFirstStage. That last one is
the only implementation of FirstStageBaseEventClass : it doesn't need
such a level of inheritance.
Deleting SecondStageBaseEventClass.

The class was merged with DetailedLogWriterSecondStage. That last one is
the only implementation of SecondStageBaseEventClass: it doesn't need
such a level of inheritance.
Modifiying write_to_logfile to write_to_stderr

Cause that's what the function does.
Renaming DwmKeybordBinder to KeyboardBinder

No need to mention dwm I think
Changing python2 to python3 in hashbang line
Merge branch 'master' into reduce_foss
Renaming KeyboardBinder into KeyboardLogger
deleted all controlkeys class as they're not in use
deleted a reference to its former parent in DetailedWriterSecondStage
Added a KNOWN_BUGS file to monitor bugs that are to be changed
Delete KNOWN_BUGS

Adding an issue on github instead
Correcting bug 'KeyboardLogger.stop() freezing'
Merge branch 'reduce_foss'
Merge branch 'master' into config_file_parser