Make imports into the CMS ignore broken modules, while still loading bad xml as error modules in the LMS

Sketchy adding of test dbs to the cms test.py config file -- these are required for the Student (shared django app) tests to run

Switch from exception logging middleware to a django signal handler, so that we no longer swallow Http404 exceptions and turn them into 500 errors

* make logging work properly in cms, dev
* fix a comment

Separate cms and lms auth and env files, and have the LMS that runs with the CMS use the CMS modulestore

Move vendor javascript into common/static/js/vendor, so that they can be shared between the CMS and LMS, and create an html template that includes all of the vendor js needed for the courseware

Split out code to replace /static urls in get_html into a separate module so that it can be used in CMS previews

Uniquify js fragments pulled from XModules, and load both XModuleDescriptor and XModule js into the cms

Add tests for the edit page for the toy course, and make sure that exporting to github sets up the git repo properly

* connect up views from student app
* Add initial @login_required decorators on the protected views
* Add tests for some of the basic functionality