Added support for object groups in the SceneLoader. "groups" is a new property in the SceneLoader result object.

Ex:
input {
  //...
  "objects" : {
    "Object.1" : {
      "groups"    : [ "Group.A" ],
      //...
    },
    "Object.2" : {
      "groups"    : [ "Group.A", "Group.B" ],
      //...
    },
    "Object.3" : {
      "groups"    : [ "Group.B" ],
      //...
    }
  }
}

result {
  //...
  groups: {
    'Group.A': [ 'Object.1', 'Object.2' ],
    'Group.B': [ 'Object.2', 'Object.3' ]
  },
  //...
}
OrbitControls: Added Firefox support. Fixes #2908.
fixed multiplyVector3Array in Matrix3 and Matrix4
SoftwareRenderer: Fixed the distortion bug and experimented wth a hacky way of passing different "materials" to the rasterer.
SoftwareRenderer: Renamed callback to shader. Inlined shader code.
SoftwareRenderer: Avoid clearing when there is nothing to clear.
SoftwareRenderer: Workaround for avoiding drawing outside the buffer.
CanvasRenderer: Fixed MeshDepthMaterial.
Added deprecated messages to more critical changes.
Updated builds.
SoftwareRenderer now features zbuffering. @rygorous ftw!
SoftwareRenderer: Small fixes.
Update docs/api/materials/MeshBasicMaterial.html

Change the docs to reflect the true default of the fog parameter in MeshBasicMaterial.
SoftwareRenderer: Removed unneded call and added compatibility methods for WebGLRenderer (uh...).
Projector: Culling vertices on the x and y axis too.
However, this can create glitches on extreme cases when the polygon is inside the frustum but the vertices are not.
Maybe this can be achieved with Box3 in a performant way?
/ping @bhouston
Updated builds.
CanvasRenderer+SVGRenderer: Removed 2D clipping for Face3/Face4 elements as the projector is already taking care of that.
SoftwareRenderer: Started to implement shader system.
Added Vector3.applyEuler() and Vector3.applyAxisAngle
Merge remote-tracking branch 'wwwtyro/patch-1' into dev