cleanup for valgrind.

ZString.h

@@ -84,7 +84,7 @@ namespace coreutils {
       /// Destructor for the ZString.
       ///
       
-      ~ZString();
+      virtual ~ZString();
       
       ///
       /// A friend method used to write the value of the ZString
@@ -454,9 +454,9 @@ namespace coreutils {
       void moveBackToLineStart();
             
     protected:
-      char *data;
-      char *cursor;
-      size_t length;
+      char *data = NULL;
+      char *cursor = NULL;
+      size_t length = 0;
       char *cdata = NULL;
       std::vector<ZString> list;