Add 64-bit numbers support to wxRegKey

This uses the native registry support for 64-bit values available since
Windows XP.

Note that SetValue64() can't be just called SetValue() as this would
introduce ambiguities when writing an int or an enum to the registry.
This could be avoided by providing overloads for all the arithmetic
types, but it's arguably better to be more clear about what exactly is
being written to the registry in this low-level class and using a
different name is definitely simpler.

include/wx/msw/registry.h

@@ -42,7 +42,8 @@ public:
     Type_Multi_String,               // Multiple Unicode strings
     Type_Resource_list,              // Resource list in the resource map
     Type_Full_resource_descriptor,   // Resource list in the hardware description
-    Type_Resource_requirements_list  // ???
+    Type_Resource_requirements_list, // ???
+    Type_Qword                       // 64-bit number
   };
 
   // predefined registry keys
@@ -197,10 +198,14 @@ public:
     // retrieve either raw or expanded string value
   bool  QueryValue(const wxString& szValue, wxString& strValue, bool raw) const;
 
-    // set the numeric value
+    // set the 32-bit numeric value
   bool  SetValue(const wxString& szValue, long lValue);
-    // return the numeric value
+    // return the 32-bit numeric value
   bool  QueryValue(const wxString& szValue, long *plValue) const;
+    // set the 64-bit numeric value
+  bool  SetValue64(const wxString& szValue, wxLongLong_t llValue);
+    // return the 64-bit numeric value
+  bool  QueryValue64(const wxString& szValue, wxLongLong_t *pllValue) const;
     // set the binary value
   bool  SetValue(const wxString& szValue, const wxMemoryBuffer& buf);
     // return the binary value