Explicit Rcpp:: in the initalize method for C++ classes wrapped inside modules. (#980)

* Otherwise the Rcpp functions are unknown when objects are initialized, unless Rcpp is attached.
* This is relevant for classes inside of modules created via Module(), both inline and in packages, but is not an issue when loadModule() is used for packages.

Author: riccardoporreca

R/Module.R

@@ -230,11 +230,11 @@ Module <- function( module, PACKAGE = methods::getPackageName(where), where = to
         .self <- .refClassDef <- NULL
         generator$methods(initialize =
               if(cpp_hasDefaultConstructor(CLASS))
-                 function(...) cpp_object_initializer(.self,.refClassDef, ...)
+                 function(...) Rcpp::cpp_object_initializer(.self,.refClassDef, ...)
               else
                  function(...) {
-                     if(nargs()) cpp_object_initializer(.self,.refClassDef, ...)
-                     else cpp_object_dummy(.self, .refClassDef)
+                     if(nargs()) Rcpp::cpp_object_initializer(.self,.refClassDef, ...)
+                     else Rcpp::cpp_object_dummy(.self, .refClassDef)
                  }
                           )
         rm( .self, .refClassDef )