Fix for adding panel to panel group via plugin

When adding panels to panel group, it should also be added to the
list of panels at the class atttribute. Otherwise, it will lose the
reference to the panels when _autodiscover() is triggered.

Change-Id: Ifa530d5a39f48d9fd9cd0ea66f6c16594447058b
Closes-Bug: #1329050
Allow forms to disable autofill in all browsers

New variable added to form to specify whether it should autofill or
not. This updates the modal forms autocomplete attribute. Hidden
fields are required because Chromium v34+ based browsers ignore the
autocomplete=off form attribute, so the hidden fields catch autofill
data. Any form without self.no_autocomplete = True will just act
like before.

Change-Id: Ibb1722023eea8f57312e1133939d1f75cd909467
Closes-Bug: 1352459
Render hidden stack parameters with a password field

In the launch stack form, any heat template parameters that are
of type string and marked as hidden are now rendered as a
password field.

Change-Id: Ie9b0a051a8815525c89de31b7ab98d8148166a55
Closes-Bug: 1362846
Merge "Fix for adding panel to panel group via plugin"
Merge "Allow forms to disable autofill in all browsers"
Merge "Render hidden stack parameters with a password field"
Merge branch 'master' of https://github.com/openstack/horizon