read_replay_JSON(): Start of same-tier support

analyze_wotb_replays.py

@@ -2443,11 +2443,13 @@ async def read_replay_JSON(replay_json: dict, args : argparse.Namespace) -> dict
 		result['enemies_survived']  = 0	# for steamroller stats
 		btl_duration = 0
 		btl_tier 	 = 0
+		btl_tier_low = 10
 		protagonist_tank  = None
 		for player in replay_summary['details']:
 			btl_duration = max(btl_duration, player['time_alive'])
 			player_tank_tier = wg.get_tank_data(player['vehicle_descr'], 'tier')
 			btl_tier 		 = max(btl_tier, player_tank_tier)
+			btl_tier_low     = min(btl_tier_low, player_tank_tier)
 
 			if (protagonist != None) and (player['dbid'] == protagonist):
 				protagonist_tank = player['vehicle_descr']