Use the ENFORCE_STACK_ALIGN_2D instead of the compiler-specific align attribute

This fixes building with MSVC.
Merge pull request #939 from mstorsjo/fix-msvc-build

Use the ENFORCE_STACK_ALIGN_2D instead of the compiler-specific align attribute
Ignore a special case for expand chroma picture under X86_ASM
Merge pull request #951 from dongzha/AddArm64UnitTestEP

Ignore a special case for expand chroma picture under X86_ASM to fix issue #947
Merge remote-tracking branch 'upstream/master' into travis.osx