uniform-grid and loose/tight double-grid impl for rust and bevy.
arrow keys: move current agent / camera
z, x: swhtch current agent
cargo run -r --example bevy_ugrid
blue: agent
green: uniform cell
red: current agent bumped other
cargo run -r --example many_ugrid
cargo run -r --example bevy_dgrid
blue: agent
green: loose cell
yellow: loose cell aabb rect
gray: tight cell
red: current agent bumped other
cargo run -r --example many_dgrid
