Fixes #1866

This was making mess with depth material.

Now that AsciiEffect also expects a renderer (like the other effects), these instructions are misleading...

As per discussion in ee946579

As per discussion here in ee946579

Promoting VTKLoader2 into VTKLoader (VTKLoader2 loads more samples than VTKLoader and is easier to maintain). 

Now it handles files with random number of spaces between numbers.

People seem to struggle with this.

We'll see if this works out :P

Anaglyph and ParallaxBarrier could also be merged somehow, as the only change is the fragment shader.

Not sure if this should be enabled by default though.