iOS: Determine render buffer resize based on CA layer, not Qt window

We resize the render-buffer based on the CALayer of the UIView that's
backing the QPlatformWindow, so the logic in defaultFramebufferObject()
to determine if a resize is needed should be based on the relationship
between the render buffer-and the CALayer, not the render-buffer and
the QPlatformWindow.

There is still an issue of the QPlatformWindow and its UIView/CALayer
not being in sync, but that's a separate issue.

Change-Id: I84f617d07ec64fea0d027473e9720523eeae0c7a
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Rename QIOSEventDispatcher to QEventDispatcherCoreFoundation

Now that it lives in QPlatformSupport, will be fleshed out more, and
might be used on OSX at some point in time. Still iOS specific, as
none of the iOS API usages have been ifdef'ed.

Change-Id: Ib7fde6403ef2dfef175a6f306a85d58027569a30
Reviewed-by: Ian Dean <ian@mediator-software.com>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
iOS: Wrap CFRunLoopSource in C++ class for easier code legibility

Change-Id: If34953b171676f0246c2fb5e60c59f59350863ec
Reviewed-by: Ian Dean <ian@mediator-software.com>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Share named time-interval constants in CoreFoundation event dispatcher

Change-Id: Ie9ae40e3f7e2631c461ad01b6e5a4640c0b773c9
Reviewed-by: Ian Dean <ian@mediator-software.com>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
iOS: Make the event dispatcher properly emit aboutToBlock() and awake()

This approach follows the same one used by the Cocoa event dispatcher.

Change-Id: I2813b09beae07d90477c9ca506924058ace13f34
Reviewed-by: Ian Dean <ian@mediator-software.com>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>