feature preview framework
Merge branches 'settings-redo' and 'feature-preview' into scratch

Conflicts:
	corehq/apps/domain/urls.py
	submodules/toggle
Add smarter handling of ES errors
Updated missing fields inn Mother MCH report.
Merge remote-tracking branch 'origin/master' into feature-preview
fix ubuntu install

- 'apt-package.txt' typo that made it not work at all
- reorganize apt-packages.txt to install nodejs correctly
change button color to blue
Merge branch 'master' of github.com:dimagi/commcare-hq into feature-preview

Conflicts:
	corehq/apps/domain/urls.py
fix validation for software plan version form
tweaks to cloudcare-as-web-user text

http://manage.dimagi.com/default.asp?107467
Merge pull request #3125 from dimagi/cloudcare-help

tweaks to cloudcare-as-web-user text
fix meta property for commtrack users
remove unused imports and meta declaration
sync south apps in post_migrate signal
fix cases__full key error
Merge pull request #3127 from dimagi/api-error

fix cases__full key error
Merge pull request #3126 from dimagi/south-design-docs

South design docs
Merge pull request #2990 from dimagi/feature-preview

feature preview framework
strip whitespace from queries
Merge pull request #3129 from dimagi/ubuntu-install

fix ubuntu install