Updates for Blockly repo changes

Per Niel Fraser: We underwent an unplanned code repo migration for
engineering reasons that broke lots of stuff. But we are back, and the move
gave us the opportunity to make a bunch of improvements. As part of
maturing, Blockly has split into two projects:

* https://github.com/google/blockly This is the core library that is being
  used by hundreds of organizations to build Blockly-based applications.
* https://github.com/google/blockly-games This is the suite of educational
  applications for teaching programming to children.

Change-Id: Ice33c6041042b0b32f6c4668f57f9e386e5dd2e2