Ported WebGL code to Three.js

Hi- following Henrik's idea I removed all low level WebGL code and moved over to Three.JS. 

Aspect of the html is similar, now has some phantom canvas to act as temp between GL and <video>s.

Three.JS creates 3 Material Meshes each one having a camera feed on it, with some pseudo perspective.

JSFeat library was added and it calculates Feature Points in image, first step for homography estimation via f.e. RANSAC (also in the library).

Finally, added an FPS/spent time calculation and display.