unify uri and path_base to just path_base

[eugene]

In a number of places we have both URI and path_base. this is ambiguous and is not really needed. Originally, we wanted to be sure we knew where The File (ie, the important file) went. But, we now have many output files that we require, so we cannot really fall-back on URI. In contrast, in some tables (eg, detStackedImfile) we have only URI, which makes it difficult (~= impossible) to find the log files or others that get generated.

There may be only a handful of places where we have only a single file, in which case we can keep only URI and not path_base in those locations.

[eugene]

see also bug #1191, which requires this fix to be in place.