association of teaser images with their titles

Teaser images are renamed according to their titles.

The image of paper titled "Implicit Skinning: Real-Time Skin Deformation with Contact Modeling" is kind of corrupted and is recaptured.

Also add an image for the paper "A Hardware Unit for Fast SAH-optimised BVH Construction", it does not have a teaser image, so I captured the first figure of it instead.

README and its generator are also updated.