EMI: Fix crash when restarting the game

ResidualVM's EMI patch installs a custom version of system_prefs.loadprefs
which maps config reads to GetResidualVMPreference() calls. The original
system_prefs.cfg is saved and used as source for default values. When
the custom loadprefs function is called a second time (i.e. when using
the New Game option in the main menu) any config read results in an
endless recursion.
ANDROID: Remove Unpacker and plugin related things

Also remove the splash screen that happend during unpacking.
GUI: Hide midi and mt-32
ALL: sync with scummvm
Merge pull request #826 from klusark/unpacker

ANDROID: Remove Unpacker and plugin related things
BINK: Use the new audio track selection API
GRAPHICS: Also add a stencil attachment to framebuffers

Note that this does require the GL_OES_packed_depth_stencil extension on
ES2. iOS supports it, and so do modern Android devices.
ANDROID: Remove old reference to removed ResidualVMApplication
ANDROID: Use custom_rules.xml instead of build.xml

The build.xml was getting ignored, so we need to actually override rules
GUI: Disable platform selection
ANDROID: Update the asset archive code to use AAssets
Merge pull request #829 from klusark/assets

ANDROID: Update the asset archive code to use AAssets
Merge pull request #827 from klusark/gui

Remove some ScummVM stuff from the GUI
ANDROID: Fix a race condition

setSurface is done in a different thread than the one that starts
the scummvm main. The main thread would then wait until the setSurface
thread notifies. The setSurface thread would notify before it actually
calls setSurface, meaning if the thread is preemted before calling
setSurface, initSurface will assert, causing the app to crash.
Merge pull request #828 from Botje/framebuffer-stencil

GRAPHICS: Also add a stencil attachment to framebuffers
EMI: Use parent sort order for attached actors

When drawing attached actors the engine uses the parent's sort order
plus one. This offset can move the attached actor behind a background
plane, for instance the chess board in the Lucre docks or Guybrush when
riding the manatee.
Merge pull request #831 from inguin/emi-attached-sort-order

EMI: Use parent sort order for attached actors
Merge pull request #818 from inguin/emi-new-game

EMI: Fix crash when restarting the game
GRIM: Fix broken overriding functions play and loadFile in NullPlayer
EMI: Handling of invalid bone names

Two animations (guy_puton_cap, guy_holdstickystuff) contain bone names
which which don't match any joints. To avoid that the holding actor is
drawn with a wrong orientation, ingore the unknown bone names when
running the animations.

Skeleton::getJointNamed() will now return null for unknown names.
The original behaviour for Actor::getWorldPos and
Actor::getRotationQuat is kept.

This patch fixes the problem, that Guybrush is "lying down" once he
holds the bottle of glue.