Parser: parse into custom dive site table

To extend the undo system to dive sites, the importers and downloaders
must not parse directly into the global dive site table. Instead,
pass a dive_site_table argument to parse into.

For now, always pass the global dive_site_table so that this commit
should not cause any functional change.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/libdivecomputer.h

@@ -42,6 +42,7 @@ typedef struct dc_user_device_t
 	bool bluetooth_mode;
 	FILE *libdc_logfile;
 	struct dive_table *download_table;
+	struct dive_site_table *sites;
 } device_data_t;
 
 const char *errmsg (dc_status_t rc);