#23 speech synthesis

* beware, it contains two commits from previous PR that is still not mergred - but it was more convenient this way
* missing translations of tts.* in HU and CZ
 * @breviar-sk @gyim please add them
* not tested with subscreens (e.g. Mary antiphones, etc.)
* speech rate can be modified on per-language basis, but only in source codes; there's no interface for that