initial lc help changes draft
making wet stuff dry a la kevin burleigh, also minor edits to help blurbs
more minor updates to language, to clarify, updated pictures, etc
more help
working on assignments help and updating some out of date content
Merge remote-tracking branch 'upstream/master' into update_help_20130412

i commiting in changes from upstream master, bc my branch is behind a couple of commits
editing assignments and schedule page
merging in latest change from kevin
Merge remote-tracking branch 'upstream/master' into update_help_20130412
learning conditions help editing
cleanup of outdated images and faq content, plus assignments and learning conditions help pages
added new help tutorials to LC help page, added or updated help images, and did general cleanup of code formatting
deleted old images
added new consent video to student video tutorials page
clarified blurbs about cohorts and sections, added learn more links to the help blurbs on feedback conditions
fixed typo in intro text
reorganized instructor getting started page, links open in new tab
edited assignments page so external help links open in new tab
changed some language on getting started page to be more clear, clarified a few things on the learning conditions help page
help blurbs for class dates
open new tabs