table map: Fixed attempt to sort over const range.
debug: Added MMC_OUTPUT_TRACE_HEADER_ as a primitive.
Added linux-ogl sandbox.

This sandbox demonstrates a straightforward ogl impl on linux. In particular,
it shows one way to wait on os messages for an arbitrary period. Currently,
it uses select and an offset, but in the future we'll need to use an absolute
time.
x11: We now use the count from XPending rather than treating it as a bool.
Updated linux-ogl to use deadline timer.

- This deadline timer is still built in terms of select, which uses
a delta. Timeouts were always accurate to within 100 ns
(.1 us, or .0001 ms), which is very acceptable.
event: Cleaned up doc on how queue works a bit.
event: Small whitespace change.
event: Queue now checks for expired weak_ptrs before dispatching.
Working through os-specific run loops and tasks.