test: fix last self.disc
fix feature read again

We have to hand the module-level read the features parameter.
Merge branch 'master' into track_class

This should merge some module-level read fixes

Conflicts:
	discid.py
create discid package / split module, re #25

This splits the discid module into multiple modules:

libdiscid.py loads libdiscid and extracts the constants
disc.py is the Disc class and related functions (read/put)
util.py has utility functsions (_encode/_decode)