Removed the Tcl intrepretor from many of the locate_modulefile utility routines.
Simplified the error code with uvec.
Added "tag" to MHash object for existence testing.
Passes all tests but 2 generate "duplicate version symbol ... found".
Merged in from the mfiles branch.
non-persistent attributes of the currently loaded modules,
regardless of the state of the loaded modules (i.e. refresh
aliases).
(still needs some test code)