Provide error message on invalid command to emmake.

Previously, this would just throw an exception, now it provides
a reasonable error message.
Statically allocate the strtok state block so it doesn't trip up our leak detection.
emcc: Improve handling of -O flag.

Previously, while gcc supports -O, emcc would fail. It now interprets
-O as -O2, just as gcc does.

Additionally, it was only looking at the first character after -O, so
nonsense like -O34 would be accepted (and treated as -O3).
Handle %c in sscanf.
Add Roger Braun to AUTHORS file.
Add TODO for missing %c functionality.
still emit library aliases - useful for e.g. gl OES aliasing, even if normally the main name is the only one used
hide verbose file packager output
Merge pull request #851 from rogerbraun/sscanf-fix

Handle %c in sscanf.
Merge pull request #860 from waywardmonkeys/strtok-alloc

Statically allocate the strtok state block so it doesn't trip up our leak detection
Merge pull request #859 from waywardmonkeys/cmdline-fixes

Cmdline fixes
Added support for `glFramebufferTexture2DOES`
turn on Math.imul by default in ASM_JS mode; it has practically no downsides since it is now used only when actually needed, which is rare, and the polyfill is very efficient
fix test_i32_mul_semiprecise
save client states in vertex array objects
wipe out previous vao-related state when binding a vao
mark client attributes as modified when we clear for vaos
GL_UNSAFE_OPTS option
remove overly-strict assertion in websockets test
typo