Start event error-detection
Validations for events!

Now an event must always have a title, start_date, and end_date.
Add validation for end_date being after start_date
Add weeks_repeat validation
Add comment, new lines
Removed unnecessary logic, better error output, fix repeat validation
EVEN better error display
Modify Gemfile, fix up controller some more, remove silly self calls

self is not necessary to be called in a model, because it is just redundant typing.

I added `gem "minitest"` to the Gemfile because ActiveSupport complained about not finding it.  It is a really weird problem that does not really make sense.  I did have it installed; I could sucessfully call `require 'minitest/unit'` in irb.  Oh well, the extra line won't harm anyone, right?  I used http://stackoverflow.com/questions/12501067/cant-make-the-rails-console-run-on-cygwin to find the answer.
Remove automatically advancing date

It turns out that this will break without more code eventually.  It's just not worth setting up right now.
Semi-revert 2bfe7e35e38, use .blank? instead of .length == 0

The commit was not completely reverted, I just removed from logic because of the validations that will prevent the cases from being possible.  Therefore, it will be a few milliseconds faster.