Add support for importing from Google Docs

[izak]

This is a replacement PR for #43 .

New entry in the Add drop down: New Google Doc Import

When that entry is clicked:

1. Google Doc picker is thrown
2. Html for selected Google Doc is fetched for google
3. Called remix's gdoc2html service which transform html into aloha-ready html
4. aloha-ready html is put into the editable area

Unresolved issues:

• Icon for New Google Doc Import is Google+ and not Google
• Using gdoc2html from http://testing.oerpub.org/ instead of http://remix.oerpub.org/ (just need to release remix)
• If the GDoc import fails (or user cancels out of the picker dialog box), we need to run some cleanup code. release does include an empty stub _cleanupFailedImport() that needs to be filled.

[philschatz]

Cool! I did the exact same thing locally, just forgot to commit it ; ) No wonder it worked for me.

[kathi-fletcher]

This is definitely better than before, but it has lots of issues that we don't have time to deal with right here.

1. It fails intermittently and no error is given.
2. Lots of patch errors are generated if you have another window open to the same repo. (This might be unrelated, but I am reporting it since I saw it.)
3. Private docs don't seem to work, or error. This might be because I am coming from my local instance. Has anyone else tested this?
4. There are long pauses -- sometimes before the picker comes up -- and always while the file is being converted. But there is no indication of what is going on. The file itself is there and someone could start adding content to it.
5. If you try a private doc and it silently fails, then if you look at another module and come back to this one, the picker comes up again. It is interesting behavior, but likely confusing.

So I want to create a new branch from master called alpha and put this there so we can demo it. We will need an alpha.oerpub.org to run it. I will make a separate Pivotal for that.