Bugfixes for payments and account status page is working!

I also added a "dues" column to the event model. All of this tomfoolery will be
fixed soon, I promise.
Payments weren't actually being properly associated with their users, thanks to
the has_one :through credit_card line that had snuck into payments.rb
Account status is pretty simple right now, though that will get better.
We need to improve the dues creation system for admins. I'm planning on refactoring
this whole project to use concerns, and creating a proper Dues class.
Modified profile_completion_percentage to use a hardcoded list of profile attributes
Merge branch 'develop' into account-status-page
Modified layout

Moved CC to the bottom since credit card is not the only way to pay and better to show billable items first. If all payment items are taken care of, display message saying so.
Merge branch 'develop' into paid-unpaid-status
Fixed the bug stopping pull request #1

When the event associated with a payment p is destroyed, p.event returns nil.
That led to nil events in the model method "user#paid_events"
Ensured that all nil events would be trimmed from the array returned from that call.
Merge pull request #9 from tmcyf/paid-unpaid-status

Paid - unpaid is now working properly.