Hello kstars developers,

kstars can not find the file TZrules.dat

I compiled kstars with this "AppDir" prefix:

    /Programs/Kstars/23.09.2017/

That means that this is similar to /usr/ as prefix,
just another prefix in use.

Upon starting kstars, a popup message shows up and says
that it could not find the file TZrules.dat. This widget
also showed where it was looking, aka the paths - this is
by the way, very helpful to me, because that way I could
instantly verify that the path is not there. And indeed,
it is not.

I was able to easily solve this by symlinking from:

    /Programs/Kstars/23.09.2017/share/kstars/TZrules.dat

Into any of the directories that the widget told me (I
picked my home dir because that is the easiest for me
to memorize actually).

Anyway, I am not sure if you guys want to fix this because
from the 0.001% of the world population, I guess only 
0.00000000001% may ever run into this. :D

HOWEVER had, it should also be trivial to fix, too, so
perhaps because it is so trivial to fix, it could be
fixed. Several ways are possible, I suggest a simple one,
to simply add the path that was picked via prefix (in
cmake this is DCMAKE_INSTALL_PREFIX=) to the paths that
kstars will check by default. This check can be omitted
perhaps if the prefix is /usr ... perhaps even /usr/local
but for any other paths, including /opt, I would recommend
to automatically include PREFIX_TARGET/share/kstars/ 
since that is where that .file will reside.

Thanks for reading anyway, please do feel free to close
this issue at any moment in time.

By the way, awesome application - I hope you guys can keep
on it. While I am not even a hobbyist dude in regards to,
well, the universe, I think it's kind of cool - a bit like
google map, of course except that mankind can not (yet) 
walk on the remote stars. I hope you can remain motivated
with kstars!