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
Merge "change how recovery animation is implemented"
allow CheckKey to request mounting /system

Also provide a default implementation of CheckKey that's reasonable
for many devices (those that have power and volume keys).

Change-Id: Icf6c7746ebd866152d402059dbd27fd16bd51ff8
Merge "allow CheckKey to request mounting /system"
update tools for making recovery images

We no longer render animations as a base image with a
possibly-partially-transparent overlay drawn over it, so delete the
make-overlay.py tool.  Now we represent them as series of images that
are interlaced by row (with a special text chunk in the PNG file
specifying the number of frames) so add the interlace-frames.py tool
to make those.

Change-Id: I866db269107a21351c3df3b4683f233f72234334
Merge "update tools for making recovery images"
remove pixelflinger from recovery

Recovery now draws directly to the framebuffer by rolling its own
graphics code, rather than depending on libpixelflinger.

The recovery UI is modified slightly to eliminate operations that are
slow with the software implementation: when the text display / menu is
turned on, it now appears on a black background instead of a dimmed
version of the recovery icon.

There's probably substantial room for optimization of the graphics
operations.

Bug: 12131110
Change-Id: Iab6520e0a7aaec39e2ce39377c10aef82ae0c595

Conflicts:
	minui/resources.c
Merge "remove pixelflinger from recovery"
separate fbdev-specific code out from minui

Isolate the code that interacts with fbdev, in preparation for adding
a new backend.

Change-Id: I19105e9da1ca6408cebc110f7e2bb5abfb481ee9
Merge "separate fbdev-specific code out from minui"
Merge remote-tracking branch 'origin/master'