Add log of game events since last load and overall

Add console command
Add to crashlog

src/saveload/extended_ver_sl.h

@@ -72,6 +72,7 @@ enum SlXvFeatureIndex {
 	XSLFI_SAVEGAME_UNIQUE_ID,                     ///< Savegame unique ID
 	XSLFI_RV_OVERTAKING,                          ///< Roadvehicle overtaking
 	XSLFI_LINKGRAPH_MODES,                        ///< Linkgraph additional distribution modes
+	XSLFI_GAME_EVENTS,                            ///< Game event flags
 
 	XSLFI_RIFF_HEADER_60_BIT,                     ///< Size field in RIFF chunk header is 60 bit
 	XSLFI_HEIGHT_8_BIT,                           ///< Map tile height is 8 bit instead of 4 bit, but savegame version may be before this became true in trunk