Do not ignore the Opts argument in elarm:start_server/1
Clarify internal function name
Avoid the need to register elarm_summary_sup...

... by teaching its ancestors how to retrieve its pid in the
supervision tree.

This removes the need for gproc, at the price of a bit more complex
code. Fixes #19.
Merge pull request #30 from lucafavatella/remove-gproc-dep

Remove gproc dependency