Qieyun-encoder

1. Regard more rhymes as 開合中立的 (phonetically neutralized): 東冬鍾江虞模尤幽
2. Add functions to encode and decode 音韻描述 (phonological description)

Temporarily disable PyLint to fix build error on Python 3.9

Repeated initials (重紐) of 匣云以母 should be null

Initial version