Add cylinder and strand representation

[gabrielelanaro]

We need to first subdivide each strand using splines:

https://github.com/HongjianLi/iview/blob/master/public/iview/iview.js#L759

then we draw strips between set of points
https://github.com/HongjianLi/iview/blob/master/public/iview/iview.js#L813

what about another kind of spline? http://threejs.org/examples/#canvas_geometry_nurbs

also the function extrude in three js may be really useful