Fixed a bug in cost computation - paths were failing to account for

their common subset.  Now we count the actual number of
transformations involved in each TargetTypeGroup


[SVN r18702]

tools/build

@@ -1 +1 @@
-Subproject commit c43dbda7372a70ddca29142cbe6ffd649d2966df
+Subproject commit 1f4c4dee0c6c286fbcde8ab92963aa23e8244fd0