Move pathname and basename utility functions to extra_utility

This makes them generally available to SICS (and it's early)

site_ansto/instrument/util/extra_utility.tcl

@@ -1,3 +1,23 @@
+# utility functions like basename/dirname in bash (dcl)
+  proc basename {node} {
+    set point [string last "/" $node]
+    if { $point < 0 } {
+      return $node
+    } else {
+      incr point
+      return "[string range $node $point end]"
+    }
+  }
+  proc pathname {node} {
+    set point [string last "/" $node]
+    if { $point < 0 } {
+      return ""
+    } else {
+      incr point -1
+      return "[string range $node 0 $point]"
+    }
+  }
+
 # Many of these functions are also useful in test and debug code
 # running on an external Tcl interpreter.
 set errorInfo ""