[LMS-57]

        Otherwise it's possible to reach stuck states.

This has caused confusion, since this file gets imported when trying to
import the requests library.  And besides, how was this file about
requests in the first place?  Helpers is a much better name.

By transparently proxying between the XModuleDescriptor and the XModule,
and between their runtimes, we can make them act as a single class, so
that we can swap in an actual XBlock instead.

LTI blade allows to include LTI components to courses.
Python integration, Jasmine and acceptance tests are included.

LTI blade allows to include LTI components to courses.
Python integration, Jasmine and acceptance tests are included.

This reverts commit 2894b21c, reversing
changes made to 34d0fe15.

According to @cpennington, no modules return anything for `get_sample_state`,
so this function is extraneous.

Currently calls the same machinery, but re-routes the logic in preparation of
deeper integration with XBlock

    And replace calls with calls to load_preview_module.

Update existing tests and provide new ones to test new paradigm.

add a 'can_execute_unsafe_code' callback method (ala LMS) to allow for whitelisting of courses with respect to codejailing