Fix is_valid_course() in multicourse_settings

* Wasn't passing coursename through to get_course_settings

Fix django-pipeline requirement url

* Add "git+" to start of django-pipeline url.  Fixes dev install on my system.

Reorganization of course tree. 
Several minor comments, but they can be cleaned up after the merge. 

Give a general purpose rake command for running django-admin in the right way for either the lms or the cms

Python leaks variables from list comprehensions (Why, Python, why?) which breaks any later attempts to use the path module

Dogfood

Conflicts:
	templates/mathjax_include.html

Sequence content does not double-escaped anymore, and eval() usage was
also removed from the sequence module.

Kf minor ui

Fix Youtube player glitches on iOS

Conflicts:
	djangoapps/courseware/capa/responsetypes.py
	djangoapps/courseware/module_render.py
	djangoapps/courseware/modules/html_module.py
	djangoapps/courseware/modules/seq_module.py
	djangoapps/courseware/modules/x_module.py
	djangoapps/courseware/views.py
	templates/main.html
	templates/problem.js
	templates/textbox.html

is completely contained within lib/dogfood, and it can be cleanly unplugged
from the rest of the code.

This prevent user from prematurely seeking the video.

This will fix the problem when user trying to click the seek button on
the iOS, as the video need to be started first before it can be
seekable.