This routine moves to the first location specified in vector list, and then draws lines between the rest of coordinates in the list. The vector list has the following format:
rel y, rel x, rel y, rel x, ...
DP = $D0
A-reg = number of vectors to draw
B-reg = scale factor to use (Draw_VL_ab only)
X-reg points to the vector list
X-reg points to next byte after list
D-reg, X-reg trashed