Fix javascript return values

Return values where wrapped by quotes because of
wrapper code used for IE compatibility.

include/wx/private/jsscriptwrapper.h

@@ -150,6 +150,8 @@ public:
 #endif
     }
 
+    const wxString& GetUnwrappedOutputCode() { return m_outputVarName; }
+
     // Execute the code returned by this function to let the output of the code
     // we executed be garbage-collected.
     wxString GetCleanUpCode() const

src/msw/webview_edge.cpp

@@ -795,7 +795,7 @@ bool wxWebViewEdge::RunScript(const wxString& javascript, wxString* output)
     if (RunScriptSync(wrapJS.GetWrappedCode(), &result)
         && result == wxS("true"))
     {
-        if (RunScriptSync(wrapJS.GetOutputCode(), &result))
+        if (RunScriptSync(wrapJS.GetUnwrappedOutputCode() + ";", &result))
         {
             if (output)
                 *output = result;