A major rewrite; more verbose explanations of context, API.

The versioning is now "Backwards": the full feature set of version 4 is documented, then the other versions' variations are described. This collects all the v4/latest features up front.
wip
Merge pull request #125 from leapmotion/protocol_docs_ideas

Protocol docs ideas - josh, dave expansion of protocol_docs
No longer run automated tests on node 0.6

"node 0.6 is not supported officially any more since some time" - has
been causing errors for us of this sort:
https://github.com/npm/npm/issues/4391
Merge pull request #133 from leapmotion/node-test-versions

No longer run automated tests on node 0.6
Merge branch 'master' into node