First pass at SDK reference documentation

Was #932. Retargetting to dev per andrerod.

*    Fixed up code comments to work with JSDoc3.
*    Created gruntfile.js with grunt tasks to build docs, launch a dev server for local testing, and to publish to github pages for the project.

Grunt tasks:

*    jsdoc - builds docs in the /docs folder
*    devserver - launches devserver on port 8888 with root at /docs
*    publishdocs - publishes /docs folder to github pages for the project. NOTE: Requires special setup. See https://github.com/thanpolas/grunt-github-pages for steps.