allow overwrite test versions but not numbered versions; handle SCRIPTS in subdirectories too; first approach on config and user interface files

version as double makes no sense because ordering with multi-digit minor numebers will be wrong anyway

new policy: conflict between test versions and explicit versions, still no conflict between test versions and implicit loaded versions with +

Fix the dbd vpath (again). Problem: circ dep when src dbd file and project dbd file have the same name (even in different sub dir).

complain for existing specific T_A only in order to allow installing other T_A (esp. EPICS_HOST_ARCH) later from other hosts