emar can receive --em-config. Don't pass along to llvm-ar.

Fixes issue #2886.
Centralize --em-config handling.

Per request of Alon.
Add glTexImage3D from GLES3.
Merge pull request #2892 from dvander/glTexImage3D

Add glTexImage3D from GLES3.
add mouseover/out events to html5.5; 1.25.2
test repeated vswprintf
reuse a single file in the vswprintf hack
Merge pull request #2887 from waywardmonkeys/emar-em-config

emar can receive --em-config. Don't pass along to llvm-ar.
[tracing] Support tracing all entry points via embind.