DElive post-jam update

Ludum Dare results are out, and so I've updated DElive with some post-jam changes. It contains some bugfixes as well as some changes to the mechanics - most notably powerups upon killing enemies, and healing is now active instead of passive.

Changes:

• Balanced and softened sound effects
• No more stuttering upon level transitions
• Slightly further shot distance
• Slightly decreased player health
• Replace passive regen with active
  • Shoot 6 boids to gain 1 health
  • Getting hit decreases kill count by 1
• Added fire rate boost
  • Shoot 3 shooties to gain 5 seconds of 2x fire rate
  • Getting hit decreases kill count by 1
• Added multishot when killing UFOs
  • Each UFO kill adds an extra shot that lasts 30 seconds
• Added visual indicator for kill chains
• Added custom cursor
• RMB will toggle autofire
  • Hold LMB while autofiring to stop firing
• Much faster level transitions (less waiting)
• Various bug fixes