Getting out of the resume game.

onLoad() is no longer called from Activity#onResume.
https://github.com/square/mortar/issues/30
Undefensive presenter code.

Presenter's onLoad() is only called when getView() is not null.
Use non-snapshot flow in sample
Update changelog for 0.7
JavaDoc, format fixes per review
Merge pull request #32 from square/ray/eager-beaver

Ray/eager beaver