ScriptWindow : Ensure ScriptWindow scriptAdded callback always runs first
ScriptWindow : Ensure ScriptWindow scriptAdded callback always runs first

Otherwise, anyone wishing to modify the ScriptWindow (via 'acquire') may
run first, create their own window, which then gets destroyed. This ensures
that we always create, configure (and properly retain) script windows.

lucienfostier/gaffer,ImageEngine/gaffer,GafferHQ/gaffer,GafferHQ/gaffer,appleseedhq/gaffer,andrewkaufman/gaffer,ImageEngine/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,appleseedhq/gaffer,lucienfostier/gaffer,lucienfostier/gaffer,johnhaddon/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,hradec/gaffer,ImageEngine/gaffer,hradec/gaffer,hradec/gaffer,boberfly/gaffer,lucienfostier/gaffer,boberfly/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,appleseedhq/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,hradec/gaffer,appleseedhq/gaffer,boberfly/gaffer,GafferHQ/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,boberfly/gaffer,hradec/gaffer,ImageEngine/gaffer