Graphical update and sprite betas

Riftwalker sprite beta, far from final version. added a  brick sprite
for a different solid theme, needs more work. ignite projectile sprite
beta. floor tile now has a more ''important'' look to it. basic floor
has a subtle graphical change. Cowardenemy sprite has been recolored
into something that doesn't hurt you eyes. (he is also more BRUH now)