File skeleton for points store app (views, templates, urls, js files, etc)
Remove duplicate store entry from installed_apps.
Fleshing out templates, models and views for store interface.
Rendering available store items, remaining points, and basic styling.
Basic purchasing from store is functional, with point deduction.
Display smaller icons for list of purchased items.
Gracefully handle 201 responses from tastypie (don't show error).
Merge branch 'nalanda-rct3' of github.com:learningequality/ka-lite into store_interface
Comment out bootstrap-subset styles that interfere with top search bar.
Style store buttons with bootstrap.
Merge pull request #2313 from jamalex/store_interface

Points store app