Fixes #265: Add Paging Indicator

Adds a new widget called PagingIndicator to visualize the progress of a
page wise navigation. The PagingIndicator is highly configurable and can
be used together with any others widgets like Swipe, TabFolder .. and
the Tabris UI.

Change-Id: I7b07e0b775ffd3acd344a3bc015894272994b05f