Updating packages and headers to match new convention

Headers have changed and packages convention as well.
This is making sure the rxandroid-framework stays in line with those new
conventions.
Move Activity and Fragment related operations to rx.android.app

This aligns the package name of Android framework classes.
Merge pull request #89 from novoda/updating_framework_to_conventions

Updating packages and headers to match new convention
Hide HandlerThreadScheduler implementation detail.
Add missing assertion to util class ctor.
Merge pull request #97 from ReactiveX/jw/hide-other-things

Hide HandlerThreadScheduler implementation detail.
Merge pull request #92 from omo/content-to-app

Move Activity and Fragment related operations to rx.android.app