Missing semicolons!
Instead of outright killing ships that hit a planet, just hurt them.
to DEATH!
Store calculated gravity constant and center position for PNBITS
Simplify / fix circle intersects check to work inside a circle
Add distance and line angle helper functions
Add initial implementation of PNBITS gravity! for #21
The calculations are quite likely totally wrong and full of awful.. but it plays decently.
Stop projectiles when they hit a planet (no hit sound yet)