st/nine: Use several constant buffers when possible

Signed-off-by: Axel Davy <axel.davy@ens.fr>
st/nine: remove some shader unused code

Signed-off-by: Axel Davy <axel.davy@ens.fr>
st/nine: better logic for loop

Signed-off-by: Axel Davy <axel.davy@ens.fr>
st/nine: Match REP implementation to LOOP

Signed-off-by: Axel Davy <axel.davy@ens.fr>
st/nine: use ISGE instead of USEQ for loops

It is more safe

Signed-off-by: Axel Davy <axel.davy@ens.fr>
st/nine: Complete and fix fog implementation

Signed-off-by: Axel Davy <axel.davy@ens.fr>
st/nine: Clamp ps 1.X constants

This is wine (and windows) behaviour.

Signed-off-by: Axel Davy <axel.davy@ens.fr>
st/nine: Handle special LIT case

Signed-off-by: Axel Davy <axel.davy@ens.fr>