begin changes to support emscripten. this includes no binding to 0 for buffers in main memory or using arbitrary texture IDs.
compile empty_dynarec where no dynarec is specified
remove texture logs
make 640x480 the default resolution
optimize VBO in glide2gl, don't upload the entire VERTEX structure when we only need a few parts of it
fix VERTEX struct in ucode06.h
Merge branch 'master' into emscripten

Conflicts:
	glide2gl/src/Glitch64/geometry.c
Merge branch 'master' into emscripten
uncomment glVertexAttrib* lines
Merge pull request #115 from libretro/emscripten

glide64 changes to support emscripten