New email,domain validation

Adds email and email domain validation tests.
Prevents volunteer submittal if using supervisor notification without a name and an email address from the specified domain.

Addresses #344.
Disabling buttons and inputs is something that doesn't work well across all browsers, especially IE8 (which your department uses heavily).  I would not include any of this disable button functionality for a number of reasons:

- Not compatible with IE8
- None of our other UI elements disable buttons until the input is correct.  Why start here?
- It is annoying for a user to have a disabled button but not to know **why** it is disabled
- There's nothing wrong with clicking submit and having the validation run to tell them what the problem is