Remember last selected indicator.

Fixes TODO by using session cookie to persist last indicator selection through
page refresh.
Refactor indicators into separate classes
Increase spray timeout to 20 minutes
Move durations helper to TimeTraveledStops class
Merge pull request #107 from WorldBank-Transport/feature/refactor-indicators

Refactor indicators into separate classes
Merge pull request #108 from flibbertigibbet/feature/cleanup-windshaft-indicators

Remember last selected indicator.
Fix version updating

There was a $scope.indicator_version that wasn't being used
Merge pull request #109 from WorldBank-Transport/feature/fix-version

Fix version updating
Remove px fallback rem function, use rems without fallback
Add indicators prototype
Make jshint happy
WIP: Copy indicator template to app
WIP: Mostly rebuilt app UI view hierarchy

TODO: Separate scope of each leaflet map
TODO: Cleanup/refactor indicator/map controllers/services
TODO: Add Django endpoints that return aggregation/type/period options
TODO: Hook new Django endpoints into indicators-[service|controller].js
TODO: Save app view state (ex: Indicators map|data)

Remove refactored map module
Return and display Agg/Type/SamplePeriod options in UI
Finish Indicator/Map controller refactor

- Moves cookieStore to OTIIndicatorsController
- Adds setIndicator function to OTIIndicatorsController
Save app state
Each leaflet map has its own state

When creating a new leaflet map via the config object,
must always call angular.extend() with an empty object as
the first argument. This creates a new object rather than
adding the new params to the config objects directly.