Godot 4.1 support; fixes minor docs/build issue with uninitialized cl…

…ass properties.

Update bulletserver docs

Add 360 degree limitation on arc width

Fixes memory leaks in BulletServers from not cleaning up bullets on d…

…estruct

Fixes memory leaks in BulletServers from not cleaning up bullets on d…

…estruct. For Godot 3.4.x.

The initial release of qurobullet!