cmn (Mandarin chinese) has been broken since 4825905.

This fix makes mandarin behave more like Cantonese. Instead of
translating characters, we search for dictionary matches.

The functionality of normal vs Chao tones should be investigated more.
Looks like latin characters as pinyin still uses Chao tones whereas
the characters in cmn_list and cmn_listx do not.

See #1044 for discussion. See also #1028 and #1163.