Scale WASD panning speed with zoom

0.25 speed was painfully slow when zoomed out
this preserves existing speed around the default+max zoom and speeds up in 0.25 increments every 10 distance, felt good to me
real speed is (still) fps dependent, notice the higher speed at the end of this clip as there's less to render
distance + speed are peeking out at the very bottom of this scuffed clip

shibbo / Fushigi