Change data and shortHelpString to adhere to naming convention

Rename data to clientData in the inlined overloads. This change is
transparent for any users.

Rename shortHelpString to shortHelp (dito for longHelp). Although this
change is in general visible for any users, Phoenix already mangles the
the parameter names to strip the 'String' suffix.

interface/wx/toolbar.h

@@ -462,9 +462,9 @@ public:
             whenever another button in the group is checked. ::wxITEM_DROPDOWN
             specifies that a drop-down menu button will appear next to the
             tool button (only GTK+ and MSW). Call SetDropdownMenu() afterwards.
-        @param shortHelpString
+        @param shortHelp
             This string is used for the tools tooltip.
-        @param longHelpString
+        @param longHelp
             This string is shown in the statusbar (if any) of the parent frame
             when the mouse pointer is inside the tool.
         @param clientData
@@ -481,8 +481,8 @@ public:
                                const wxBitmap& bitmap,
                                const wxBitmap& bmpDisabled,
                                wxItemKind kind = wxITEM_NORMAL,
-                               const wxString& shortHelpString = wxEmptyString,
-                               const wxString& longHelpString = wxEmptyString,
+                               const wxString& shortHelp = wxEmptyString,
+                               const wxString& longHelp = wxEmptyString,
                                wxObject* clientData = NULL);
     //@}