Emitter now has minParticleAlpha and maxParticleAlpha values for setting a random alpha on emitted particles.
Emitter.particleAnchor allows you to control the anchor of emitted Particles. Defaults to 0.5 (same as before) but now under your control.
Emitter now emits Phaser.Particle objects instead of Phaser.Sprites, which can be extended as required.
Emitter has had various local properties removed that were already declared in Phaser.Group which it extends.