change how recovery animation is implemented

Instead of one 'base' installing image and a number of overlay images
that are drawn on top of it, we represent the installing animation
with one PNG that contains all the animation frames, interlaced by
row.  The PNG is expected to have a text chunk with the keyword
'Frames' and a value that's the number of frames (as an ascii
string).  This representation provides better compression, removes the
need to subclass ScreenRecoveryUI just to change the position of the
overlay or number of frames, and doesn't require gr_blit() to support
an alpha channel.

We also remove the 'indeterminate' progress bar used when wiping data
and/or cache.  The main animation serves the same purpose (showing
that the device is still alive); the spinning progress bar has been
redundant for a while.

This changes the default recovery animation to include the
antenna-wiggling and gear-turning that's used in the Nexus 5 recovery
animation.

Change-Id: I51930a76035ac09969a25472f4e572b289418729

Conflicts:
	screen_ui.cpp
	screen_ui.h