Sandbox environment

-un-ignore from repo
so that folks have a place set up for them
to mess around with the library
TileAnimation: do not automatically preload layers

Preloaded has a couple of significant downsides
- Can cause application to freeze up when adding
  multiple layers (in Safari, this was causing
  application to crash with 3 layers)
- Additional bandwidth costs for Aeris API servers

This commit completely disables preloading. However, the 'preloadLayer_'
method is left intact, if we want to provide some type of
interface for preloading layers in the future.

If you are considering preloading, I would try to think of some way
to prevent setting too many layers to the map at once -- I believe
this is what is causing the performance issues. Instead, maybe
set layers to map at a setInterval
Animation: do not change from/to bounds when times are loaded

- this is making a big assumption about how the
  client wants to handle new animation times.
AutoUpdateAnim: Trigger 'autoUpdate' after times are loaded

- instead of waiting for all layers to be loaded
minor typo
Add missing AMD dep
AerisApiModel#parse: handle cases where collection is leveraging Model#parse
LightningCollection: sort by date/time

- by deafult, Lightning collection will
  grap models at the center of the within/ bounds.
  Sorting by date/time provides more distributed results.
MarkerCluster: Accept offsets style configuration
Define icons for 'funnel' and 'downburst' storm reports
Fix BatchModel docs

- `models` option is no longer used. Instead pass in
  models as attribute values
MockJSONP#stubAerisJSONP

- Allows using MockJSONP as a global replacement
  for the aeris.JSONP object.
MockMap: set default attribute values
Stub Aeris API response objects
findClosest utility method
TileAnimation#goToTime uses layer in same time era (past or future)

- Fixes an issue where going to a time in the past
  (or the current time) could show a forecast layer
  (or vice versa).
Add docs for using the sandbox environment
Update version to v0.7.8