Support SDL audio sample size of 512 samples. Make the SDL audio buffer queueing logic more resilient for jitter, and factor out a common parameter 'SDL.audio.numSimultaneouslyQueuedBuffers' that can be used to tune for a good quality<->latency balance.
mention inline asm() syntax in EM_ASM comment
Merge pull request #1816 from juj/fix_test_other_warn_undefined

Fix test other.test_warn_undefined on Windows.
Add a configuration option Module.SDL_numSimultaneouslyQueuedBuffers to allow user code to configure how many SDL audio buffers to keep simultaneously queued up for the audio backend. More buffers means less change of starving (and cracking audio), but increases latency. Fewer buffers lower the latency at the risk of playback glitches. Make minimum audio buffer size 128, which should be way below anything reasonable already. Clean up commented out code.
Merge pull request #1806 from juj/sdl_audio_queueing

Sdl audio queueing
ignore llvm ir fast-math notation; fixes #1762
remove obsolete demos folder
precise clock_gettime when not using CLOCK_REALTIME; fixes #1795
Fix HTTP server in browser harness to serve files with appropriate header and body content by using the python built-in SimpleHTTPServer for file serves instead of manually crafting header+body. Fixes browser test harness runs on Windows and Linux.
Relax emcc --compression cmdline parameter on Windows to autodetect encoder and decoder file suffix so same cmdline works on Windows and Linux. Fixes browser.test_compression on Windows.