adds attending filter for calendar
allows calendar to switch months
updates calendar to only grab events one month at a time
Get events in a month when user passes in date

Event#for_month was requiring and event month and year as arguments and also getting events from the first of
the next month.

* Change Event#for_month from a class method to a scope
* Require date argument for Event#for_month
* Handle invalid date parameters in event_controller#index
Merge latest master

*Add Calendar object to build calendar for view

Conflicts:
	Gemfile
	Gemfile.lock
	app/assets/javascripts/application.js
	app/assets/stylesheets/application.css.scss
	app/models/event.rb
Merge remote-tracking branch 'upstream/master' into events-calendar
Handle invalid dates in events_controller#index

When an invalid date is passed into the date parameter
for events#index, it will now revert back to the current
date.
Merge pull request #72 from steven-ferguson/events-calendar

Display events as a calendar
Fixes #19