audio/py-eyed3: update to 0.7.4 (backwards incompatible branch)
- copy audio/py-eyed3 0.6.18 to audio/py-eyed3-06
- update audio/py-eyed3 to 0.7.4
- chase dependency change of audio/abcde to use audio/py-eyed3-06
- drop maintainership of audio/py-eyed3-06
- add mutual CONFLICTS into a both ports