switched to using events from event emitter for summaries.

users, polls and competitions now use events. eventemitter is pretty great
corrected spelling of achievements
using mapReduce for score calculation

mapreduce aggregates the correct votes for a competition. once that is done we
emit an event to user stats and competition summary to store those values.
storing rank in competition stats for ease of use.
removed event emitter subclasses.

I was using event emitter incorrectly and can handle what it was being used
for with regular functions instead of emitting events. seems cleaner to me.
should refactor poll summaroes, competition summaries and user stats into a
generic finder.
Merge pull request #10 from paulgrock/summary-events

Summary events