studio - settings: matched up styling/treatment of disabled input fields in schedule/details settings view to new advanced settings UI

studio - advanced settings: removed new/delete controls from advanced policies and makde key fields readonly/disabled since we're now showing all policy metadata

Conflicts:
	common/lib/xmodule/xmodule/course_module.py

Update of Delft logo (lighthouse ticket #234)

Fixed undefined variable error in choicegroup.html

Set grading policy to an empty dict if it can't be decoded from json

Need to trigger invalid instead of error, after changes for new version ...

Fix lettuce tests so all studio ones are working and faster

Return children from timelimit module definition_from_xml in the new format (separate from definition)

Add datadog metrics capture around heartbeat timing

Fix lettuce tests to work with phantomJS