[client] Move cshift info from viddef to viewstate

It makes much more sense for cshift state to be in viewstate because it
is very much an effect rather than anything specific to a renderer.

include/client/view.h

@@ -61,6 +61,8 @@ typedef struct viewstate_s {
 	int         powerup_index;
 	cshift_t    cshifts[NUM_CSHIFTS];	// Color shifts for damage, powerups
 	cshift_t    prev_cshifts[NUM_CSHIFTS];	// and content types
+	quat_t      cshift_color;
+	qboolean    cshift_changed;
 
 // pitch drifting vars
 	float       idealpitch;