First pass at bulk saving fields.
Fix runtime tests
Fix up the core tests to handle new XBlock.
Add new test for error handling in save.

Fix some bugs found while writing these tests.
Move workbench `render` to default XBlock `render`
Add some runtime handle tests.

pep8 fixes
Write tests for runtime render, handle

New view counter XBlock and test refactoring.
Add runtime test
Address comments; violations
Address comments; violations
Address comments; violations
Rename KVS.update to set_many
Address more review comments
Address review comments
Modify XBlock.__delete__ method