fix typo

lib/raweat.hpp

@@ -447,7 +447,7 @@ public:
         pnum[byi] = (int)datbuf[(unsigned long int)(numfl*sizeof(dattype)+byi)];
       }
 
-      // add number of array
+      // add number to array
       datmes_.push_back((double)num * factor + offset);
     }
   }