italian voices problems, fix request

[sysnaz]

While this command:
espeak-ng -s 120 -v it "c'è qualcosa che non funziona se fosse allergia dovuta alla parietaria giudaica?"
works but with a robotic voice, this command:
espeak-ng -s 120 -v mb-it3 "c'è qualcosa che non funziona se fosse allergia dovuta alla parietaria giudaica?"
which more natural voice, has the following problems:
mbrola: Warning: ts-i/ unkown, replaced with -
mbrola: Warning: i/-o1 unkown, replaced with -
mbrola: Warning: O1-ss unkown, replaced with -
mbrola: Warning: ss-e unkown, replaced with -
mbrola: Warning: r-i/ unkown, replaced with -
mbrola: Warning: i/-e unkown, replaced with -
mbrola: Warning: r-i/ unkown, replaced with -
mbrola: Warning: i/-a unkown, replaced with -

that seems mbrola related. There are similar problems in mb-it1, mb-it2 and mb-it4 voices.

[valdisvi]

eSpeak NG passes phonemes, which are not defined in particular MBROLA voice. To work around that look at https://github.com/espeak-ng/espeak-ng/blob/master/docs/mbrola.md#2-add-mbrola-phoneme-translation-file