Make descriptorsystem inherit from Runtime
Switch to studio_view
Refactor wrap_xmodule call
Merge branch 'master' into jkarni/fix/descriptorsystemruntime
Merge branch 'master' into jkarni/fix/descriptorsystemruntime

Conflicts:
	cms/djangoapps/contentstore/views/preview.py
Merge pull request #567 from edx/jkarni/fix/descriptorsystemruntime

Make descriptorsystem inherit from Runtime