A regression from 2afda54 and friends was that you couldn't use the
extra keys and then directly use the keyboard, you would have to click
in the session first.
This commit restores the correct behavior and also adds a visual queue
to the fact that the screen got the focus by fading the controlbar.
Toggling the enabled state is a remnant from an earlier version
of the code where we could determine if the the session is actually
clipped, and not just that the setting is enabled.
Right now we only change things based on the setting, so let's
completely hide the button when clipping is disabled.
It is not relevant for the connection stage so it should not have
been a constructor argument to begin with. Ship with a warning for
a release before we remove it.
* First attempt to make the fullscreen button work inside an iframe.
* Cleaner distinction between document element and document.
* Scoping corrections. Auto-detect correct iframe.
* Added comments to the relevant sections.
* IE issue fixed.
* Same source issue solved. fullscreenToggle now checks if it is permitted to inspect other iframes.
