Refactor for Asynchronous control flow

[RobinIsTheBird]

Rollbar registered the following error:

java.lang.NullPointerException: Attempt to invoke virtual method
'void com.google.android.gms.maps.GoogleMap.moveCamera(
    com.google.android.gms.maps.CameraUpdate)'
on a null object reference

at org.azavea.otm.ui.MainMapFragment.lambda$null$3
    (MainMapFragment.java:488)

It's probably a race condition. Tame the asynchronous control flow to eliminate race conditions.

AFAIK, this fixes all race conditions except open question #1 below. Unknown how many rollbar errors it will eliminate, but should eliminate the original npe.

Refer to

• MapView
• GoogleMap
• MapsInitializer
• GoogleApiAvailability
• Fragment Life Cycle

Changes:

• Use jDeferred to synchronize between asynchronous flows
• Move most initialization from onCreateView to onActivityCreated
• Move google api connect, map fetch, and add mode cancel to onStart
• Update MapHelper to use current google availability api

Open questions:

1. Need a way to manage the MapHelper google api dialog to determine whether the play store services problem gets resolved, and fail catastrophically if it doesn't.
2. Need a way to test missing play store services without wrecking my phone.
3. Fails to fix # 297, clearing the filter repositions the camera
4. Probably shouldn't create new Deferred objects if they already exist, but haven't noticed any negative effects of doing so
5. I don't know enough about the tile cache to be sure when it needs to be cleared.

--

Connects to #294

[RobinIsTheBird]

If this rev passes review, I'll rebase/squash onto master.