Updated Polish translation

Added some strings I missed last time (my poedit not showing
 strings with msgctxt) and fixed a few typos.
I believie it is really complete now.

Signed-off-by: Krzysztof Arentowicz <k.arentowicz@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Documentation: update list of supported divecomputers

Taken directly from the libdivecomputer website...

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>