Add SoundEncoder from nupic.research

[DefinitlyEvil]

Class file: https://github.com/numenta/nupic.research/blob/master/htmresearch/encoders/sound_encoder.py

Although it is under research repo, we can still track its development. Maybe we should put its java class in package name to something like org.numenta.nupic.encoders.expirientmental.

[cogmission]

@DefinitlyEvil Sounds good :+1:

We have a "research package" already, org.numenta.nupic.research --> we should put it in org.numenta.nupic.research.encoders.

Other than that, this is fine. Did you want to take a crack at this?

[DefinitlyEvil]

Well, since this is a poring job, I guess I might wanna give it a shot. xD

[DefinitlyEvil]

Plz look at gitter (htm.java) room.