Small packaging improvements

pack.bat

@@ -1,5 +1,5 @@
 @echo off
-IF NOT EXIST 7z.exe GOTO EXIT
+IF NOT EXIST 7z.exe GOTO NO7Z
 IF NOT EXIST "Twitch Drops Miner.zip" GOTO NEW
 7z u "Twitch Drops Miner.zip" "Twitch Drops Miner/" -r -x!"Twitch Drops Miner/cookies.*"
 GOTO TEST
@@ -9,5 +9,8 @@ GOTO TEST
 :TEST
 7z t "Twitch Drops Miner.zip"
 GOTO EXIT
+:NO7Z
+echo No 7z.exe detected, skipping packaging!
+GOTO EXIT
 :EXIT
 exit %errorlevel%