Next step towards working translations

This may seem like a really odd change - but with this change the Qt tools
can correctly parse the C files (and qt-gui.cpp) and get the context for
the translatable strings right.

It's not super-pretty (I'll admit that _("string literal") is much easier
on the eye than translate("gettextFromC", "string literal") ) but I think
this will be the price of success.

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

Just to make sure there's no confusion - we are NOT calling gettext. We
are calling tr from a gettext like interface.

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

These were created by converting the exting translations from po to ts
lconvert po/xx_yy.po -o subsurface_xx_yy.ts
and then merging in the new strings
lupdate subsurface.pro

You convert those into .qm files with lrelease and then localization
should work. Of course a good bit of new strings are still untranslated -
and lots of Gtk strings are still included.

This still needs to be included in the build system.

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