broke up CG_Init to enable JS event loop to breathe
async-ified FS_Startup
added JS platform to build
misc SDL fixes until SDL 1.2 headers are fixed in emscripten
fixed diffuse variable reference
added get / set methods for stdinIsATTY so it can be accessed by the JS layer
don't use default master servers
use different default sound due to so many missing assets
namespaced libc functions in bg_lib to prevent collisions with emscripten
updated entrypoint definitions to compile properly with emscripten
added major vid_restart fast hack to enable responsive window resizing
temporary renderer workaround for https://bugzilla.icculus.org/show_bug.cgi?id=6083
rough first pass at JS vm compiler