Post-Jam update with minimap and more juicy polish

I've continued to work on the game to add some more quality of life features and polish that I was wanting to see - with the minimap being the most-requested feature.

Below is a rundown of the changes in this version:

• Added minimap
• Mouse panning
• Added visual base upgrades
• Implement player laser colours
• Re-balanced ship DPS
• Added engine VFX
• Unit spawn VFX
• Add explosion VFX
• Shoot from all guns at once
• Add background asteroids

That's the majority of what I was hoping to get into the game. Future changes may come if I want to add more depth or I get enough player feedback.