Animate image scale and bounds

This commit properly animates images with different aspect ratios.
By default, regular scale animator is used which scales up or down the entire ImageView.
If `animateClipBounds={true}` is specified on the **to** `SharedElementTransition`, instead of scaling the View, the actual Drawable bounds and scale is animated which prevents the image from appearing distorted during the transition.

This reverts commit 82492de4ee.

My ignorance

Summary:
The old path only work for 'example-redux'

This is a temporary solution to #292

Adds BottomTabActivity which replaces TabActivity
Adds a dependency on `com.aurelhubert:ahbottomnavigation:1.2.3`
Uses iOS tabsStyle, with additional parameter that allows toggling of whether to show the titles of inactive tabs

The approach we took is fairly simple. Navigation is created natively in corresponding activity,
currently only TabActivity is supported, and we pass the styling parameters and screenId to it.
Each screen is rendered in its own ReactRootView and is wired to the same ReactInstanceManager,
so all screens share the same java script context.