Distorted Android

First attempt at the MeshBase.apply(VertexEffect) API.

Remove the MeshBase.{set/get}Stretch API altogether.

Fix for a crash when exiting an app:

Activity.onPause() -> MessageSender.stopSending sets mThis to null, then a last message gets sent and a crash in newMessage().

Fix this by

1) making the Message inner class static (so that we can create a new one without a reference to mThis)...

Change the Postprocessing effects: separate the radius and the halo.
Reason: we needed a way to specify the size of the halo around a postprocessed object; before it was automatically (and not very correctly) computed from the radius - before we knew the size of the object's bounding box, so this automatic computation was possible. Now we're removing the MashBase.getBounding(0 API, so the size of the halo has to be explicitly given by the user. This way is more correct anyway and gives the user more control (as the Multiblur app proves!)...

Simplify a bit the place where we got a crash once.

A lot of changes.

1) main vertex shader: remove support for degree_object. This functionality will hopefully come back when we introduce other than circular regions.
2) MeshBase: remove the need to set a Bounding box (this is the point of the whole thing - we wanted to get rid of this so that the advances in MeshJoined will be easier)...

new VertexEffectShear

new VertexEffectScale

bugfix for VertexEffectRotate

new VertexEffectRotate