Allows building non-min-size builds with Emscripten.
Adds ENABLE_GLSLANG_WEB_DEVEL.
Moves the glslang.js files to OSDependent/Web.
Small cleanups and docs update.
This adds build rules to support generating a WASM binary to be used
on the web. The API exposed to web applications is definated in the
new glslang.js.cpp file.