Fix checking for AVX support. We also need to check if the XCR bit is set as well.
Fix crash in GLSL when overlays with many textures are used.

Have to call shader->use() for each set_coords or we overflow
the attribs array cached buffer.
Include strcasestr.h in compat.c.
(Xbox 1) Render 'messagebox' text in menu disp now - position
text better
don't update overlay ranges until all events are polled
fix overlay alphas for multiple button presses
(iOS) The frontend settings menu now only displays cores with a custom config attached. A “Create New Config” button is used to create a new config for a core.
(iOS) Add initial MFi game controller support.
Get rid of non-normalized snes-landscape
(Android) Change default overlay for Android to snes/snes.cfg
(Android) Make some tweaks to input drivers for conformity
(XDK) Implement analog code
(frontend.c) Some cleanups
Fix some fast-forward overlay radiuses.
Fixup overlays with correct quickmenu.
Style nits.
(OSX) Build fix
Rework frontend - separate functions now for iterating per frame
and for doing teardown - Emscripten and Apple ports can make use
of this now so we don't need separate frontend implementations
(iOS) Make apple_gamecontroller 'backwards compatible' with iOS 6
by doing runtime check for iOS version and then returning early
(iOS) Remove default_libretro_path and default_libretro_info_path defaults. Having them causes the the -L argument to RetroArch to not be picked up.