Support webkit gamepad api
Review changes
add javascript implementation of glutSetCursor function
fix indentation
handle all possible GLUT cursor value and throw an exception when an invalid one is provided
general fixes to FAQ and some of the getting started articles
Merge pull request #2706 from hamishwillee/incoming

general fixes to FAQ and some of the getting started articles
remove some unnecessary trailing commas
clarify returnType for ccall/cwrap; fixes #2705
Pass -Wno-warn-absolute-paths when building libcxx and libcxxabi to avoid the spamming absolute path warnings on first time build, which could easily be confused as the compiler having hung in an infinite error loop, since there are hundreds of these messages being printed.
Merge pull request #2434 from Daft-Freak/gamepad_chrome

Support webkit gamepad api
Fix native OSX builds in test_sockets.py. For OSX, when our own-compiled fastcomp Clang is invoked to build a native executable, we must pass a command line parameter to it to tell which OSX SDK we are targeting.
Fix bad signature of emscripten_set_socket_error_callback() in emscripten.h
Silence a lot of the absolute path include warnings by always accepting any path that has the directory emscripten in it.
Merge pull request #2696 from anlambert/glut_set_cursor

Add support for glutSetCursor function
Remove support for old Mozilla Audio Data API which is not longer available in Firefox.
Remove the use of Web Audio API ScriptProcessorNode for queueing buffers. It doesn't improve in practice, generates a new set of compatibility bugs and is limited to one sampling frequency only (which the browser either matches or doesn't match at random). Keep the code simple and use a unified path for SDL audio in all audio frequencies.
Improve SDL audio queueing to not only rely on setTimeout()s to queue new audio data, but also try to queue new audio at the end of each requestAnimationFrame. Since rAFs fire at every 16 msecs tied to vsync interval, this should give a much better granularity for audio streaming.
Reduce the SDL buffering delay to 50msecs to make the audio latency smaller.
Optimize memory usage in library_gl.js to avoid unnecessary 2MB temp memory buffer from being created when neither FULL_ES2 or LEGACY_GL_EMULATION is defined.