Support x86 build with VS 2015

Pass extra assembler flags to the asm tool in msvc toolchain

My first commit so added my name to the AUTHORS file.

Change-Id: I19529a901be6d9c00df3c0880003be3363475c6e
Reviewed-on: https://skia-review.googlesource.com/114740
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
2 files changed