Initial implementation of RandomDistributedScalarEncoder

Initial implementation of random distributed encoder. Hotgym works well with it, but not fully debugged yet. Tests in process.
Tests and bug fixing
More tests and pylint cleanup
Completed test cases
Removed debug code
Removed useless check for int
minor corrections in the comments
Random encoder updates

Changed s to the more description name 'resolution'.
Fixed bug in returning bucket indices (added tests
to catch this bug.) Updated hotgym parameters.
Merge pull request #522 from ugurthemaster/patch-1

minor corrections in the comments
Simplified computeOverlap
Merge pull request #520 from subutai/random_encoder

Random distributed encoder
A typo has been fixed.
A typo has been fixed.
Merge pull request #527 from ugurthemaster/master

Minor corrections in the documentations.
Adding CONTRIBUTING.md

Fixes #479.
Merge pull request #529 from rhyolight/add-contributing-doc

Adding CONTRIBUTING.md
Merge branch 'master' of https://github.com/numenta/nupic