Changes to text in disclaimers

Changes the disclaimers on the pre-registration page to reflect
Anthrocon's badge policies.
Change reg confirmation to AC-specific text

Changes the registration confirmation emails to match what Anthrocon had
last year.
Add confirmation template

Adds the confirmation template to this plugin so the confirmation text
can be changed.
Change confirmation text

Updates the confirmation text to match AC's requirements. However, it
does not display the badge numbers or the charge amount correctly.
Add extra disclaimer.

Adds information about AC's non-profit status to the disclaimer page.
Fix confirmation email

Changes the contact email to reflect Anthrocon's real contact email.
Fix cost variable

Changes the cost variable so it will actually work, based on the changes
to preregistration.py.
Merge pull request #7 from Anthrocon-Reg/change_text

Text changes