Peter fogg/explicit course settings

Use new feedback notification when changing section release dates.

Fix/cdodge/update localdev setting for unsafe courses

Jonahstanley/refactor unittest courses

Remove use of keyword "delete" in forum coffee code to fix IE8 bug LMS-441

Unskip Acceptance Tests

seems like we need to define COURSES_WITH_UNSAFE_CODE in cms.envs.common.py, although cms.envs.common.py imports lms.envs.common (where this is defined).

adding option for file based backend

Fix course team JS to handle non-200 status codes

Also fixed things in the toy course where needed

Factories were used when possible but tests depending on importing or things not manageable by factories used the toy course.  New files were added to include the needed functionality.  Most files are blank or have minimal xml needed to work

A blank asset file was also added to toy

This fixes the following tests(T stands for toy, F stands for factory made):
T import_textbook_as_content_element (needed to add a textbook to toy)
F static_tab_reordering
T import polls (needed to add a poll to toy)
T xlint_fails
F delete
T about_overrides (needed to add an about override to toy)
F remove_hide_progress_tab

Make sure that changing grading cutoffs triggers a save confirmation, and reliable reverting of changes.

Rather than asynchronously saving when a setting is updated, we now
prompt the user to confirm their changes and only persist the data if
they hit the save button. Lettuce tests are updated to expect this
behavior and some new ones are added.

When all settings require an explicit save, this functionality will be
shared between each view (with slight changes, e.g. click handlers.)

Change client-side code references from "delete" to "_delete". Some of these
were method names (or would generate method names), which breaks in IE8
because "delete" is a JavaScript reserved keyword. foo["delete"] is ok, but
foo.delete is not. This also makes forums marginally functional in IE8,
though the left-nav still has some display issues.

Parameterize aws s3 bucket name for forum uploads

Jonahstanley/acceptance tests unique database

Add support for Vagrant install, and switch from RVM to rbenv