Merge remote-tracking branch 'aosp/upstream-master' into update-shaderc

Includes:
37422e9 Support building under CYGWIN
e0e4044 Update Travis notification emails
f8cc397 Generate spvasm.vim

Test: checkbuild.py on Linux; ran unit tests on Windows
Change-Id: If82c790d58064940397123732219bdffa29ab988