fixed bug when creating static mappings of elements to graphics

fixed bug when creating static mappings of elements to graphics

This bug showed up with wrong mapping for "mm_pacman.eating.right" (as
defined in "src/conf_gfx.c") in auto-conf file "src/conf_e2g.c" being

  {
    EL_MM_PACMAN,                       ACTION_EATING, -1, FALSE,
    IMG_MM_PACMAN_EATING_RIGHT
  },

where it should correctly be

  {
    EL_MM_PACMAN,                       ACTION_EATING, MV_BIT_RIGHT, FALSE,
    IMG_MM_PACMAN_EATING_RIGHT
  },

instead. This problem was fixed by always using the calculated direction
(which can still be "-1" if no direction is specified).