Bug 1063356 - Update libvpx update script. r=kinetik

Remove upstreamed patches, rebase stdint.patch.

Update script to work with the most recent chrome pull, upstream
hasn't been doing releases, so this is the next best way to stay
current.

It's no longer possible to build vp8 and vp9 in the same unified
source file, so most of the vp9 code is moved out of unified
sources.
Bug 1063356 - Update libvpx source. r=kinetik

Results of running ./update.py --ndk ~/android/android-ndk-r9
    --commit c731d6a4f19eea861ceb2ff31399420b2452eb74
Bug 1063356 - Update libvpx build flags. r=kinetik,ted

Propagate ssse3 and sse4.1 build flags from configure.
This is required by new optimations in upstream commit
c731d6a4f19eea861ceb2ff31399420b2452eb74.
Bug 1063356 - Disable libvpx AVX2 support on linux. r=kinetik

Temporarily disable AVX2 simd acceleration on linux to work around
issues with old toolchains on the integration server builds.

Linux valgrind and B2G desktop builds use an older gcc which doesn't
support the new AVX2 intrinsics. This can be resolved either by updating
the build, or splitting the target platforms into AVX and no-AVX variants.
Bug 1063356 - Pass -mfpu=neon when building libvpx. r=kinetik,mshal

This is required to compile the new intrinsic-based simd acceleration
code for arm.
Bug 1063356 - Define __ANDROID__ for libvpx asm. r=kinetik,mshal

The assembly relies on __ANDROID__ to decide whether to call
'lrand48' or 'rand'. The later is available on desktop but
only on Android L or later. However, this macro isn't defined
by the linux vpx_config asm file we use for x86 Android builds,
so we must pass it manually when invoking yasm.
Bug 1084245 - Introduce a hacky opt-out of the new security checks for MozTCPSocket. r=bz