remove unused variables from Raycaster.
add Plane.flip() plus unit test.
add Frustum.containsPoint, containsSphere + first Frustum unit tests.
polishing frustum to a first class member of math.
more Frustum unit tests + minor optimization to Plane.
always use local var planes = this.planes in Frustum. fix common include to require Sphere before Frustum.
Merge branch 'dev' of git://github.com/mrdoob/three.js.git into frustum-additions

Conflicts:
	src/math/Plane.js
fix sign/comparison in Frustum.containsSphere and add unit tests.
rename Plane.flip() -> Plane.negate() per @mrdoob
expand Frustum.contains() per @alteredq, @gero3
move credit for barycoord function from Raycaster to Triangle per @mrdoob.
remove unused variable from Frustum.js
Frustum.contains -> intersectsObject, containsSphere->intersectsSphere, removed Frustum.containsAnyPoints, .transform.  Update unit tests accordingly.