Make region dimensions the same type as positions

There are just far too many warnings issued for signedness differences
for it to be practical to cast every time.
Unsignedness was hiding the issue of dimensions being larger than
positions could express anyway.

region.hpp

@@ -31,7 +31,11 @@ namespace util {
     template <typename T>
     struct region {
         typedef T position_type;
+#if 0
         typedef typename always_unsigned<T>::type size_type;
+#else
+        typedef T size_type;
+#endif
 
         T x, y;                 
         size_type w, h;