Make dive edit message box tex more concise

commit 3c064d58578f ("Make the message when editing a dive fit better")
kinda fixed the wrong problem. A better solution was suggested - just drop
the instructions regarding Cancel / Safe. It's quite obvious what to do
mow that the buttons are part of the message.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Parse localized GPS string

Let's ALWAYS support the somewhat "international standard" N/S/W/E
characters, but ALSO support localized versions.

Fixes #315

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