setup: Remove *.txt from MANIFEST.in
setup: Remove *.txt from MANIFEST.in

Previously used to include dev-requirements.txt.

mopidy/mopidy,jodal/mopidy,jcass77/mopidy,jodal/mopidy,mopidy/mopidy,kingosticks/mopidy,kingosticks/mopidy,kingosticks/mopidy,jcass77/mopidy,jcass77/mopidy,adamcik/mopidy,adamcik/mopidy,mopidy/mopidy,jodal/mopidy,adamcik/mopidy