Improve version reporting

[oxtopus]

nupic should have a first-clas API for reporting version details, including its nupic.bindings dependency. Something like the following would be very helpful:

>>> nupic.version()
'0.7.0.dev0'
>>> nupic.getNupicBindingsDependency()
'0.6.2.dev0'
>>> nupic.bindings.version()
'0.6.2.dev0'

This way, users may self report installed versions and compare. Even better if there were a way to determine commit sha, too, if installed from source.