- XSLT is now used for transforming SSML into what must be provided as input to the TTS processors, instead of in-house SSML serialization ;
- The TTS processors that cannot handle marks do no longer split SSML themselves. It is now done in the threads that call the TTS processors, and they transform SSML into SSML, rather than text ;
- The marks are now mutable, as they are stored in a dedicated class, instead of map entries ;
- Use Iterables instead of Collections when the PCM chunks are concatenated ;
- Fixed a leak when a MemoryException occurs.

Fixes #6
Needs the branch called 'XSLT' of pipeline-framework.