Added ZString.c_str() function; Added MStrin operator=.

File.h

@@ -3,6 +3,7 @@
 
 #include <string>
 #include <fcntl.h>
+#include "ZString.h"
 
 ///
 /// File
@@ -16,6 +17,7 @@ namespace coreutils {
 
     public:
       File(std::string fileName, int mode = O_RDONLY, int authority = 0664);
+      File(ZString &fileName, int mode = O_RDONLY, int authority = 0664);
       ~File();
       void setBufferSize(size_t size);
       void read();