[orca-list] Some enhancements when using the generic modules of speech-dispatcher

[Didier Spaier <didier slint fr>]

Hello list,

recently a few patches landed in speech-dispatcher that hopeful close a few issues, including for orca users.

Mostly in concern are users of mbrola voices, although the scope be all synthesizers using the generic module 
of speech-dispatcher.

What have changed (in speech-dispatcher master on git):

The list of available generic voices is actually provided, either directly, for instance
spd-say -o espeak-ng-mbrola-generic -L lists the available mbrola voices available.
They are also displayed in he Orca screen reader preferences tab Voices/Person and a voice can actually be 
selected in this list.

This is true also if the default synthesizer is set to espeak-ng-mbrola-generic and the vocal synthesizer is 
set as Default synthesizer in Orca preferences voices.

More specifically, for a mbrola voice to be listed it should be actually installed.

I have tested this only with espeak-ng-mbrola-generic and pico-generic.

If you find any issue, please report it here or in the speech-dispatcher mailing list.

Best,

Didier