Use wx-prefixed macros throughout the repository.

Change {DECLARE,IMPLEMENT}_*CLASS and {DECLARE,BEGIN,END}_EVENT_TABLE
occurrences to use the wx-prefixed version of the macros.

tests/exec/exec.cpp

@@ -154,7 +154,7 @@ private:
         long wxExecuteReturnCode;
     };
 
-    DECLARE_NO_COPY_CLASS(ExecTestCase)
+    wxDECLARE_NO_COPY_CLASS(ExecTestCase);
 };
 
 // register in the unnamed registry so that these tests are run by default