Cleaned up file paths to match newrelic and added ubuntu init.d script.

I modified all file paths to reside in the existing NewRelic directories and match NewRelic formats. For example:
/etc/newrelic_plugin_agent.yml  ==> /etc/newrelic/newrelic_plugin_agent.cfg

I also added an init.d script for Ubuntu/Debian that is based on /etc/init.d/newrelic-sysmond.

Does it make sense to also change from underscores to hyphens to match NewRelic program names?