Google Drive XBlock - Fake PR for review purposes, do not merge!

@martynjames Created this PR for the review. 

Btw for the future, it's easier to create this when the first commit is empty. Also, if we want to review a series of PRs at once instead of individual PRs, it would be easier to merge the individual PRs in a branch which isn't master, and then create a PR from that branch into master when it's ready -- this way we don't need "fake" PRs at all, they represent the actual review workflow.
You might want to upgrade the lxml version to match the one from edx-platform: https://github.com/edx-solutions/edx-platform/blob/af777420d2e4f53f1a8e1daa899ac60441ce7803/requirements/edx/base.txt#L45