Update: new flying enemy, updated graphics, bugfixes.

What's new:

• The flying enemy is now a ghost, which is bigger, turns red gradually after each kill and self-destructs after the 4th kill.
• New graphics for both barrels and the cannon.
• Barrels are now jump thru instead of solid, so players can walk through them, but can still jump on top of them. This also means players can no longer get stuck under falling barrels.
• Improved player-box and player-mine collision detection.
• Bugfix: player animation glitch while wall riding, in placement mode and rotating a placeable wall overlapping the player (thanks Zsozsó!).
• Bugfix: player animation glitch when entering placement mode while going either left or right.
• Bugfix: players in placement mode still collided with projectiles (eg. cannonballs).