Added new exception

[[Imported from SVN: r4768]]

common/exceptions.hh

@@ -190,6 +190,11 @@ namespace Dune {
    */
   class OutOfMemoryError : public SystemError {};
 
+  /*! \brief Default exception if a function was called while
+   * the object is not in a valid state for that function.
+   */
+  class InvalidStateException : public Exception {};
+
 } // end namespace
 
 #endif