Fix the Github CMake build

Restore the wxDEBUG_LEVEL defines for the module builds.  It is
currently required (see explanation in CMakeLists.txt)

Add explanantion of why wxWidgets_USE_REL_AND_DBG=NO is needed
for the Github Windows build.

Further restrict the disabling dynamic loading for Windows and Mac
of the Lame and FFmpeg libs.  Some corrections need to be made in
ExportMP3.cpp (and probably some for FFmpeg as well).

And don't build mod-nyq-bench or mod-null by default until they
can be fixed.  (They fail to build.)

cmake-proxies/mod-script-pipe/CMakeLists.txt

@@ -22,6 +22,13 @@ list( APPEND INCLUDES
 list( APPEND DEFINES
    PRIVATE
       BUILDING_SCRIPT_PIPE
+
+      # This is needed until the transition to cmake is complete and
+      # the Windows pragmas are removed from ScripterCallback.cpp.
+      # Without it, the wxWidgets "debug.h" will define __WXDEBUG__
+      # which then causes this module to emit library pragmas for the
+      # debug versions of wxWidgets...even if the build if for Release.
+      wxDEBUG_LEVEL=0
 )
 
 list( APPEND LIBRARIES