Voicefile generation: implement string corrections.

Voicefile generation now can correct strings for the TTS system similar
to what voice.pl does. The current implementation has some limitations:
- only implemented for voicefile creation.
- the corrections file is built in and can't get changed.
- string corrections can be disabled in the configuration dialog.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30628 a1c6a512-1295-4272-9138-f99709370657

rbutil/rbutilqt/base/rbsettings.cpp

@@ -48,6 +48,7 @@ const static struct {
 #else
     { RbSettings::Tts,                  "tts",                  "espeak" },
 #endif
+    { RbSettings::UseTtsCorrections,    "use_tts_corrections",  "true" },
     { RbSettings::LastTalkedFolder,     "last_talked_folder",   "" },
     { RbSettings::VoiceLanguage,        "voicelanguage",        "" },
     { RbSettings::TtsLanguage,          ":tts:/language",       "" },