Add a hidden preference to skip the Spiderweb logo at startup

The same preference also skips the scenario editor startup splash
In order to enable that, the scenario editor now loads prefs.

src/scenedit/scen.main.cpp

@@ -25,6 +25,7 @@
 #include "choicedlog.hpp"
 #include "scen.menus.hpp"
 #include "res_image.hpp"
+#include "prefs.hpp"
 
 /* Globals */
 bool  All_Done = false;
@@ -101,7 +102,7 @@ static void init_sbar(std::shared_ptr<cScrollbar>& sbar, rectangle rect, int pgS
 void init_scened(int argc, char* argv[]) {
 	init_directories(argv[0]);
 	init_menubar();
-	// TODO: Sync and load prefs
+	sync_prefs();
 	init_shaders();
 	init_tiling();
 	init_snd_tool();
@@ -151,7 +152,8 @@ void init_scened(int argc, char* argv[]) {
 		load_graphics();
 		cDialog::init();
 	});
-	run_startup_g();
+	if(get_bool_pref("ShowStartupLogo", true))
+		run_startup_g();
 	init_thread.join();
 	set_cursor(sword_curs);