v0.965

A variety of additions this week:

• DAS is an inverted SAD shot. It starts where it would have ended and then travels backwards to where it should have started. Because it starts by dealing damage and then spawning the bullet, it can potentially hit twice.
• DUP repeats the last shot you fired. This has interesting consequences when it's in the first slot.
• The Caster mob fires different types of bullets depending on where the player is. It's meant as a counterpart to the player, so if I add more types of enemy shot, I may add these to the Caster's range of weapons.
• The Splitter mob looks like a fat Walker mob, but it splits into two Runners on death.
• The Runner mob moves fast and will leap across gaps.
• The Waller mob leaves a wall behind when it dies.
• A meta-progression altar will spawn at the start of the next level when your first shot isn't SAD, presenting you with the same shot from that slot.
• Levels are now numbered from 1 upwards. Internally it's just adding 1 to the displayed value so this won't affect your progress.

And more chunks and bug fixes.