Turner Helm [Alpha 2]

This update adds the turner_helm. It can't be attacked when it's facing you. It's a rather obvious enemy (or ally) that many games have where you have to attack something from behind to defeat it, so I've added it to the game as I also needed to upload a fix for a significant bug with virus spawners.

Fixes:

• Spawner-virus wasn't spawning on its virus spawn step
• Teleporter enemy gfx updated (looked too similar to a powerup).
• Fixed glitch-in on level select to cover parts that stick out (like keys).