edx/edx-platform — pull request #3227 by FiloSottile (2014-04-04 23:18:41+00:00)
Title: Enforce type of the XBlocks Fields when set

This updates the XBlock dependency to edX/XBlock@cba8d788f0c16802b4cc468ccb6dc765b62e55e8 and add the newly introduced enforce_type methods

**Please see edx/XBlock#200 for rationale and details.**