region: remove vector addition operator

It is unclear what this operator was supposed to do, and triggers a
number of sign and type warnings. Re-add later if necessary under a more
descriptive name.

region.cpp

@@ -43,16 +43,6 @@ region<T>::region (T _x, T _y, size_type _w, size_type _h):
 }
 
 
-template <typename T>
-region<T>&
-region<T>::operator+= (const vector<2> &rhs) {
-    x += rhs.x;
-    y += rhs.y;
-
-    return *this;
-}
-
-
 //-----------------------------------------------------------------------------
 template <typename T>
 typename region<T>::size_type

region.hpp

@@ -42,8 +42,6 @@ namespace util {
 
         region (T _x, T _y, size_type _w, size_type _h);
 
-        region& operator +=(const vector<2>& rhs);
-
         size_type area     (void) const;
         size_type diameter (void) const;
         void scale (double factor);