introduce template bundler (fixes #67) and cube template (fixes #49)

[cvan]

r? @jcarpenter @dmarcos @ngokevin

[cvan]

I can imagine these things not getting DRY. thoughts?

[ngokevin]

what case could this get out of hand?

[cvan]

more examples of Polymer's "templates":

https://github.com/GoogleChrome/ioweb2015/blob/21d7a80a/app/elements/io-gallery.html
https://github.com/GoogleChrome/ioweb2015/blob/21d7a80a/app/elements/name-cycler.html
https://github.com/GoogleChrome/ioweb2015/blob/21d7a/app/elements/io-toast.html
https://github.com/GoogleChrome/ioweb2015/blob/21d7a80a/app/elements/experiment-fab.html
https://github.com/GoogleChrome/ioweb2015/blob/21d7a80a/app/elements/elements.html

[cvan]

updated: added vulcanize to output a single HTML import

now the dev has to keep track of two files: the dist/vr-components.js and dist/vr-components.html. read this article and the comments; great discussion about this inherent issue with dependency management of imports for sharing, reusing, and in our cases releasing a library.

I think this is sufficient. I can simply undo the vulcanize commit in this PR and just ship all the HTML inline in the JS which is what I was doing before.

thoughts? I'm looking to merge this ASAP and we can iterate as we continue to develop.

[cvan]

post-push feedback welcome. feel free to provide feedback, ask questions, and file issues for enhancements desired.

[cvan]

r+