iOS: Refactor qioswindow.mm into quiview.mm and quiview_accessibility.mm

Change-Id: Ib6297e37d67b2c0ea251ae054b8ff877af2673a5
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
iOS: Fix compilation with Xcode6/iOS8 SDK

We were implicitly including OpenGLES/ES2/glext.h prior to iOS8.

Change-Id: I353badb5c209b9ebc57c1718223c164590705064
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
iOS: Add helper for getting the iOS platform integration instance

Change-Id: I550d345ab0f8bcba1225c425464e198d43d9fda8
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
iOS: Detect external screen connections and expose as additional QScreen

The additional QScreen can not be used for anything yet, since we don't
set up a window and root view controller for it.

Change-Id: I335b796bdd89fc58a27ec4e20c5ed355be0cab66
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
resoureces.prf: use small resources (though cpp file) for xcode

currently there isn't a clean solution yet to support object files
or architecture specific files during the preprocess step when
using the xcode generator.
This fixes ios resources (but will break with large resources).

Task-number: QTBUG-39835
Change-Id: If620ab0c3b5c1f92db8f7b4740061c807730db57
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>