Major Commit - See extended description.

Added Visualiser manager ('n' to cycle through visualisations).
Added 3 new shaders (Barrel Distortion, Chromatic Abberation and a basic
one)
Added Two new Visualisers (VCR and Tunnel)
Fixed problems with audio FFT (specifically logarithmic re-binning)
Added some image files that are used by the visualisers (also, they are
generic and probably reusable.)

Tested on an ATI Radeon 5650, because there is some shader work being
done, installation on an nVidia chipset may require some shading tweaks.