To enable undo of dive site functions, it is crucial to work
with different dive site tables. Therefore add a dive site table
parameter to dive site functions. For now, always pass the global
dive site table. Thus, this commit shouldn't alter any functionality.
After this change, a simple search for dive_site_table reveals all
places where the global dive site table is accessed.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>