Better Support for Profiling Long-Running Processes

Thanks to @jfenc91 statsd-jvm-profiler now has better support for use with long-running processes. The new features include:

1. Port incrementing to find the next free port for the embedded HTTP server if the specified port is unavailable.
2. Better exception handling for errors when emitting metrics. A new endpoint is available to retrieve these error messages.
3. Endpoint to track the number of recorded metrics