Fix build when QIMAGEREADER_DEBUG is enabled in qimagereader.cpp

If QIMAGEREADER_DEBUG is enabled in qimagereader.cpp, the build fails.
There are wrong variables in qimagereader.cpp:314,395

Change-Id: I22498c49fbfecb3799dc5cabf374486bb715ded7
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Cocoa: Simplify qt_mac_cgimage_to_nsimage code

Since 10.6, NSImage has a sensible contructor for that.

Change-Id: Ie753135ebb37630c1a70c395689bf85d4a4a01de
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Cocoa: Let Cocoa pick the right pixmap for menu item icons

Task-number: QTBUG-31477

Change-Id: Iac2d13b68d36c691b60685b69cd390958c35fae3
Reviewed-by: James Turner <james.turner@kdab.com>
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>