Refactor map page to support different interaction modes

The main "map" page has several modes -- browse trees, add a tree, and edit tree details. Each mode has a div in the sidebar to show its UI and a JS module to handle UI events. The "modesForMapPage" module initializes the mode modules and orchestrates switching between modes.

Note that different modes will interpret map clicks differently. We pass the map's "clickedLatLonStream" to each mode, but filter it so the events will be ignored unless the mode is active.
Reference subtemplates correctly
Expose settings object to templates

This is used to give access to the bing api key for non-instance based
apps where settings.js doesn't get loaded.
Whitespace cleanup on css
Add in openlayers css
Remove instance-related controls from base template
Instance names must be unique
Add function to approve bulk audits
Remove center field, just use the bounds instead
Use actual keys for delete-permission testing
Mark instance config as 'blank allowed'

When a value is required it gets inserted into the database
automatically. This just bypasses the django verification.
Merge pull request #234 from ahinz/topic/updates

Topic/updates
Rename file
Merge pull request #233 from RickMohr/map-page-supports-modes

Refactor map page to support different interaction modes
Update reference to renamed file