[uima-as] dd2spring doesn't properly handle urls in import by location which are absolute

UIMA Descriptors have <import> statements. One variety of these is import by location. The location can be relative or absolute; if relative, it is relative to the location of the file having the <import> statement.

dd2spring handles this by keeping track of the importing file's file path, and (for relative urls) using that as the "base" to be relative from. It has a heuristic test for determining if a path is absolute: it looks for a path that starts with a "/" or something like "c:/"

The CDE, when you import something outside the Eclipse workspace, uses the URL format "file:/c:/xxxx/etc" This is an "absolute" location, but the dd2spring code's test for this fails.