Added support for chrome tracing by integrating the
minitrace library (github.com/hrydgard/minitrace),
and modified it with a background flushing thread that allows
tracing to continue automatically after the predefined
1 million event limit.
Menu items and an accelerator (Ctr+T) have also been
added. Starting and stopping the trace simply replaces
trace.json with the new trace data.
The feature is disabled by default. Pass MINITRACE=y
to the build command to enable it. Some traces are
already added as an example, however they won't have
any effect if the feature is disabled.
