Fix "IE doesn't keep you logged in between restarts (or page reloads)" problems by disabling cookie check in iframe.  issue #2218 & issue #2183

Fix the user going back to the "enter email" state if they select an email using auto-complete and then type CTRL-C on the email address.

* Move the "passwords do not match" on the set password screen above the first password.
* Move the "this email address and password do not match" above the email field.

removeListener throws in IE8

only Firefox seems to make the placeholder text
be the same color as the normal text, so this will
set the placeholder to a lighter grey

fixes #2187

* sites_signed_in => number_sites_signed_in
* sites_visited => number_sites_remembered

* Disable the email field.
* Focus the first password field instead of the email field.
* If no email is stored (user did not come from /signin or /signup), redirect the user to /signin.
* If email address that is stored is not known, redirect to /signup.
* If email address that is stored is known but a primary, redirect to /signin
* When calling User.addressInfo on a primary address, check whether the address is known or not.  Allows us to simplify the forgot page.

* Remove the 250ms animation time.
* Update/fix unit tests.

fixes #2132

Give the Persona window the name __persona_dialog when opening. Useful for Selenium tests which need an easy mechanism to get a handle to the window being tested.

* Slide the password fields down whenever they are shown.
* Add slideUp/slideDown, fadeIn/fadeOut to dom-jquery.js

* Remove the signup page and all remnants of it.

* If the user types in a known secondary, redirect the user to the signin page.
* If the user manually clicks the "new to persona?" or "Existing account?" links, clear the stored email address.

* If the user enters an unknown secondary email, redirect them to the /signup page.
* If the user arrives with a known secondary email in storage, show the password field.

* Vertically center the layout again.
* Apply the -webkit-text-size-adjust to the body.
* Remove the background-image gradients on the body.
* Reduce the vertical height of the "Use another address" button.

fixes #2116

improve i18n of main site - strings for translators should not include site implementation details (links, ids, etc) - this prevents accidental breakage and allows us to change our ids and links without requiring retranslation.  closes #2093

When a secondary email is verified, make sure its verified bit is set to true.  Lots of cleanup for readability.