This adds basic support for using the OS X' TTS system. The current
implementation does only support selecting the voice itself, no further
settings (like speed pitch / speed) adjustments are implemented. As OS X' TTS
system wants the strings to get spoken in 8 bit encoding problems with locale
combinations are possible. For this better error handling in the rbutil TTS is
needed. The voice test button in the configuration dialog reacts pretty slow
due to the way its speaking is done. This can get changed but also requires
adjustments in the rbutil TTS system.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24979 a1c6a512-1295-4272-9138-f99709370657
