Change activition property calls to be pointer based

Change activition property calls to be pointer based

After longer discussions, we actually found out that
passing Values by reference (ie. as pointers) is most
likely quite a bit more efficient then passing them by
value. This is esp. true on 32bit platforms.

So change the runtime back to a pointer based calling
convention.

Change-Id: I948d361b6876109d77fc58f11ceb47109cf631d1
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>