Update 'Run.sh'

Run.sh

@@ -1,8 +1,9 @@
 #!/bin/bash
 SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 OUTPUT_DIR="$2"
-CFG_FILE="$3"
 DEFAULT_CFG_FILE=UnrealTournament.ini
+CFG_FILE="${3:-$DEFAULT_CFG_FILE}"
+
 function add_iniKeyEx() {
 	crudini --set $OUTPUT_DIR/System/$1 $2 __$3 $4
 	# Warning: ugly hack with sed to allow multiple key instances + to remove space around '='