Bindings refactored

[david-ragazzi]

Fixes #1616.

This PR was created to simplify #1579 . Its objective is prepare bindings folder to c++ extensions build using setuptools.

Detailed changes in logic order:

• Removed C# and Java outdated (and not supported) bindings. This change involved copy content from bindings/EngineInternalCommon.i into bindings/py/EngineInternalPy.i and bindings/py/algorithms/AlgorithmsImpl.i into bindings/py/algorithms/AlgorithmsPy.i
• Remove IORange binding. It is not used by any module at nupic.
• Move python bindings from $NUPIC/extensions/bindings/py into $NUPIC/nupic/bindings. Default setuptools pratice is that all c++ extensions should put into package structure.
• Rename all *.i implementation files to snake_case. This is not required itself, but improve the readibility as they are now within nupic package structure and also generated wrappers and shared libraries names are derivations of their names: engine_internal.i => _engine_internal.so, engine_internal_wrap.cpp.
• Update CMakeLists.txt with the changes above.

CC: @rhyolight @oxtopus @scottpurdy @subutai

[rhyolight]

LGTM, but I want @scottpurdy to approve, which might take awhile because he's swamped with other work.

[scottpurdy]

@david-ragazzi - thanks for pulling these changes out, this is much easier to review (albeit still quite a big change). Let me give it another look now

[david-ragazzi]

Thanks @scottpurdy , I'm pulling make remotion still today..