Explicit State Particle System Prototype

Reworked my particle system to send baked relative velocities (relative to accumulated velocity at the sample point) instead of absolute positions. Now I can do cool effects like gravity, increasing gravity over time, cutting off the baked data and letting the system settle with drag, and turbulent wind forces. This will actually make it easier to integrate into UE, since the sim shader there does a similar process of adding in velocities to get the final motion.