Created ResetController.

closes #2412

- Updated the reset route to accept token parameter and hand it over to the controller.
- Added ResetController which handles the submit action and the button disabled state.
- Added reset action to the user model to handle ajax request.
- Updated reset template.
- Added fixtures to test reset API action.
- Fixed password variable names to camel cased style (e.g. newpassword -> newPassword).