Overload Protection

Since PR: https://github.com/andytill/erlyberly/pull/112

erlyberly will suspend tracing when it detects an overload. Detection is done by checking the process message queue, if the number of queued messages is higher than the number configured in the maxTraceQueueLength property in the .erlyberly2 configuration file then dbg is stopped.

The number of functions that will show in erlyberly will be half of maxTraceQueueLength because the call and return of the function are separate messages.

The UI will drop traces that it has received if it holding more than the integer value of maxTraceLogs which defaults to 1000. This is to avoid situations where the UI accepts an unlimited number of trace logs and eventually runs out of memory.