This removes these words from dictionary and uses translation rules
instead. Result is to shorten the i.

See #1337 and #1388.

1. Rewrite cmn_rules. Vowel will be spoken as Mandarin only when it's
with a tone number. Otherwise, it will be regarded as English. This will
make English words translated more correctly.
2. Fix issue of word item in cmn_listx not taking effect.
3. Fix dictionary_skipwords bug. It should be injected when re-structing
method TranslateWord3.

See #1388 and #875.

Add some rules and exceptions for italian language.

Closes #1194.

Windows: add mto dict

Russian: improve numbers and add words

Code cleanup: relocate functions & remove unused #defines

Fix vowels link

Note: Strange that FLAG_ALT7 is used but ALT4-ALT6 are not. Same with
R6p.

utf8_nbytes() is only used in dictionary.c. Others are moved to common.c

fix compilation on windows

fb06936c b52d1f3afd and c4d8976fbc broke it.

Russian: fix regressive voicing assimilation and number 8