add libtiger to the contribs

add libtiger to the contribs

I've added libtiger to the contribs setup, but since it depends
on Pango and Cairo, building it fully via contribs if those
dependencies are not there already will be tricky.

add kate/tiger to debian, fedora, unix,
as they're quite likely to build and run fine there
both are known to work on fedora
libkate is reported to work on darwin too, but i'll shy
away from adding it there as it's too circumstancial

also, do not run autoconf for libkate, it ships an up to date configure

Signed-off-by: Rémi Denis-Courmont <rdenis@simphalempin.com>