Small optimization to the particle iterator.
Minor tweaks to Direct3D9 PointSpriteRenderer.
Direct3D9 PointSpriteRenderer now effectively clips particles which are not active (pixel shader does not execute due to PSIZE < 1.0).
Emitter no longer calculates position for particles which have expired.
Tweaked Direct3D9 sample app.
Per particle scaling is now supported.
Tweaked Direct3D9 sample app.