Fix incorrect AMD dep
minor: autoformat
aeris.util: Create a safe copy, to prevent overriding shared underscore AMD module.
Test clock: override underscore.now instead of aeris.util.now

- aeris.util uses _.now
Update version to 0.7.3
Merge branch 'master' into dev
minor code refactor
TileAnimation: change AnimationLayerLoader option

- accepts AnimLayerLoader constructor instead of instance

Allows us to recreat the object with new parameters
(will be necessary for dynamic from/to values)
AerisTile#autoUpdate event
minor: auto reformat
MERGE: Test clock args
Test clock accepts arguments for sinon FakeTimer
Pull out mocks from TileAnimation spec:

- MockAerisTile
- MockAnimationLayerLoader
DateHelper#getTime
minor TileAnimation restructure
TimeLayersFactory: turn off autoUpdate on cloned layers
Animation#getFrom, #getTo
MockTimes fix
Leaflet tile: turn off `reuseTiles` option

- Causes memory leaks when trying to destroy
  (Leaflet stores tile objects in memory)
Animation#setFrom, #setTo

- Update to MockANimatino
AutoUpdateAnimation

- Includes refactoring to AnimLayerLoader, TimeLayersFactory,
  which allow from/to bounds to be updated

- AnimationSync uses AutoUpdateAnimation object by default