Merge branch 'master' of https://github.com/RcppCore/Rcpp

Author: kevinushey

inst/include/Rcpp/vector/ListOf.h

@@ -86,6 +86,10 @@ class ListOf {
         return list.end();
     }
 
+    inline int size() const {
+        return list.size() ;    
+    }
+    
     class ListOfProxy {
 
     public: