creating unique utterance ids

I'll put these commits here until I send them through sourceforge...

We wanted to keep the .raw files for improving the acoustic models so we traced why they were always 000000000.raw in https://github.com/batumi/KartuliSpeechRecognition/issues/15 and found that we could pass the utterance id here, and thus create unique files. 

The consequence of this is that all the utterances are maintained on the SDCARD so the users of the pocketsphinx-android library will need to add their own flushing routine to remove old files periodically to reduce disk consumption.

On the other hand, having unique utterance ids seems like a useful feature for when you receive partial hypotheses back.