fixes #1857 simple reordering of top menubar
Use divider for dropdown links for clearer UI
fixes #1859 left-nav link for quiz with children is now into list view

at an appropriate place.

Quiz with no children maintains old behavior
remove vestige of testing
initial commit
db-based S3 cache (#1440)

Working but since each request is a DB hit, unclear if it will ever be
that much faster.  Will try local django cache instead.
remove vestigial calls for news and video on course home
Merge pull request #1872 from Stanford-Online/jbau-leftnav-handle-exam-variations

fixes #1859 left-nav link for quiz with children is now into list view
#1843 ajax-tized left-navbar loading, (still not quite cachable)
Merge branch 'master' of https://github.com/Stanford-Online/class2go into jbau-ajax-leftnav
Merge pull request #1876 from Stanford-Online/wescott-master-exercise-work

Wescott master exercise work
Merge pull request #1870 from Stanford-Online/kluo-dropdown-divider

Use divider for dropdown links for clearer UI
django local fs cache for file and video locations (#1440)
fix typo in default (unused) cache defn (#1440)
strip querystrings from file links (#1440)
fix comment: 4 hours, not 40 :) (#1440)
remove unnecessary calls that get data for left navbar
Merge pull request #1869 from Stanford-Online/jbau-simple-reorder-topnav

fixes #1857 simple reordering of top menubar
fix typo in removing_querystrings; remove from default case too (#1440)
fix: return values from dl_links_all had swapped params (#1440)

Caught by @jbau in code review.