Try to ensure all traces written before reset

* Checks traces delivered on all nodes before reset
* Flushes tracer file port to disk
* Waits for local process tracer to exit (i.e. to finish writing)
Make API and match spec consistent

* Uses {trace, disable, enable} to mimic Dbg.trace/2 and Dbg.clear/1
* Allows shorthand atoms in match spec
* Adds nicer errors for bad flags
* Removes circular modular dependency between Dbg and Dbg.MatchSpec
Fix printing of trace messages

* Handle returning to `:undefined` mfa
* Use Exception to format exit
* Correct tense of third party linking messages
* Print register/unregister names using inspect, not to_string
* Handle `:undefined` caller mfa
* Remove extra space before non-app stacktrace entries
Add tests
Bump version to 0.14.1