Changing ImageStream -> ImageDataStream and creating ImageStream.

To pipe data into an image matrix, you now use ImageDataStream.

ImageStream is now a stream that transforms image buffers into matrices.
Add shortcut for face cascade file -> cv.FACE_CASCADE
unit test for imagestream
Fix path
provide image to event
Merge branch 'provide-cascades' into beta

Conflicts:
	lib/opencv.js
beta 0.0.11
Allow video capture to be streamed