iprt,vboxmanage,manual: Try write the iso maker docs as a docbook refentry document. Tried to generalize the vboxmanage refentry output handling, moving it to RTMsg*. Made VBoxManage and IPRT generate their C/H sources in their own Makefiles. Hacked the C/H source generation till it can deal with the rather different RTIsoMaker command structure (no sub or sub-sub command stuff).
