package/cups-filters: add image printing support

Enable image filters, to directly print images from cups.

Signed-off-by: Alexey Lukyanchuk <skif@skif-web.ru>
[yann.morin.1998@free.fr:
  - explicitly enable it, don;t rely on defaults
  -  reword commit log
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>