modules - ibmtts: manage the synthesis_voice speech parameter
modules - ibmtts: manage the synthesis_voice speech parameter

This patch manages the synthesis_voice parameter in the ibmtts module.

The speech-dispatcher "SET SYNTHESIS_VOICE" service selects a voice according to its name which is more accurate than the "SET LANGUAGE" service which selects a voice according to its language (iso 639-1, two alphabetic characters, e.g. en for english).

"SET SYNTHESIS_VOICE" is currently the only service for differentiating voices with distinct variants or dialects (e.g. British English or American English).

Signed-off-by: Gilles Casse <0d39f276d04dddaab21686f383b1af6a7ca124ba@oralux.org>

razr/speechd,razr/speechd,razr/speechd,razr/speechd