Run pre-load hook before testing for modifications

The pre-load hook is often used to manipulate the data files before
loading, such as by synchronizing with a remote calendar. Make sure we
always execute the pre-load hook upon reloads, even if the data files
have not been modified.

Fixes GitHub issue #98.

Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

src/calcurse.c

@@ -619,7 +619,11 @@ int main(int argc, char **argv)
 	config_load();
 	wins_erase_status_bar();
 	io_load_keys(conf.pager);
+
+	run_hook("pre-load");
 	io_load_data(NULL);
+	run_hook("post-load");
+
 	io_unset_modified();
 	wins_slctd_set(conf.default_panel);
 	wins_resize();