Cleanup: Remove 'BKE_library.h' include from 'BKE_main.h'

That kind of implicit includes should really only be done when totally,
absolutely necessary, and ideally only with rather simple 'second-level'
headers.

Otherwise not being explicit with includes always end up biting in
unexpected ways...

source/blender/python/intern/bpy_interface.c

@@ -58,9 +58,10 @@
 
 #include "BKE_appdir.h"
 #include "BKE_context.h"
-#include "BKE_text.h"
-#include "BKE_main.h"
 #include "BKE_global.h" /* only for script checking */
+#include "BKE_library.h"
+#include "BKE_main.h"
+#include "BKE_text.h"
 
 #include "CCL_api.h"