Adding disable logic for buttons.

Update tests, clean up approach.

Updating jasmine tests.
Add Selenium tests for the combined login/registration form.
Merge pull request #5959 from edx/will/logistration-selenium

Logistration: Bok-choy tests for the combined login/registration page.
Merge pull request #5962 from edx/sanchez/disable-login-button-on-click

Adding disable logic for buttons.
Password reset Selenium tests
WIP: moving password reset tests into login tests