Small array cleanups
Small array cleanups

Remove duplicated code from Array copy constructor and protect
assignment operator against self-assignment.

Change-Id: I0de2cbc54cbfed570a2166c63237f264792dc144
Reviewed-by: Lars Knoll <a812617a4072dcbeb80684eca0f369f0083af109@digia.com>

mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative