hikaru/gpu: annotate instruction 103.

Information kindly provided by DreamZzz.
hikaru/{gpu,renderer}: implement poly types.

Barely. I think they require deferred rendering (a la PVR/dreamcast) to work
properly.

Also added a visual debug option to color models depending on their type,
predd 'm' to toggle.
hikaru/renderer: remove useless comment.
hikaru/renderer: remove "random color" debug option.

It was only useful to grasp the geometry when everything is white (i.e. in the
viewer, in absence of valid materials and texheads). Use the "draw normals"
option instead, it's much better.
hikaru/renderer: implement (somewhat) A8 textures.

Used in PHARRIER intro. Not quite right (read, the sizes specified by the game
do not match with the current interpretation of the texture format).