Add:Core:New vehicle type null

[navit-package] / navit / vehicle / Makefile.am

SUBDIRS=
if VEHICLE_ANDROID
  SUBDIRS += android
endif
if VEHICLE_IPHONE
  SUBDIRS += iphone
endif
if VEHICLE_DEMO
  SUBDIRS += demo
endif
if VEHICLE_FILE
  SUBDIRS += file
endif
if VEHICLE_GPSD
  SUBDIRS += gpsd
endif
if VEHICLE_GYPSY
  SUBDIRS += gypsy
endif
if VEHICLE_NULL
  SUBDIRS += null
endif
if VEHICLE_WINCE
  SUBDIRS += wince
endif