BPython:

- as proposed by Ton, default dir for menu enabled scripts is:
userhome/.blender/scripts if available or (using bprogname -- argv[0]),
blenderInstallationDir/.blender/scripts/ otherwise.
- moved a piece of code from BPY_interface.c to BPY_menus.c to get rid
of a linkage warning reported by J. Walton
-- added the first scripts to release/scripts:

We need time to get more scripts there, but the situation should improve
consistently from now on.  Adding three export scripts: cal3d, directX, ac3d.
And one import: ac3d.

source/blender/python/BPY_menus.h

@@ -96,5 +96,7 @@ void BPyMenu_RemoveAllEntries(void);
 void BPyMenu_PrintAllEntries(void);
 char *BPyMenu_CreatePupmenuStr(BPyMenu *pym, short group);
 char *BPyMenu_group_itoa (short group);
+char *bpymenu_gethome();
+struct BPyMenu *BPyMenu_GetEntry (short group, short pos);
 
 #endif /* BPY_MENUS_H */