More little bits of dev

Worked more on those arrows (They’re now bright red, with a white outline, and have animations as they appear and disappear).  Fixed a bunch of internal VectorStorm engine bugs which had been stopping roads from drawing for the past few days, and was also breaking the bounding box generation for a lot of MMORPG Tycoon’s procedural building geometry (potentially could have resulted in bad clipping, but I’ve never actually noticed that happening).

Also implemented a vsMatrix4x4 multiply, and a few other matrix-related functions that I thought I needed (but turned out not to).  The functions had been declared as existing since forever;  I just apparently  never remembered to actually define them in case somebody actually wanted to use them.  I still haven’t tested them;  for all I know, they could be totally broken, still!  Must get around to testing those, eventually.  (I’m pretty certain that at least my vsMatrix4x4::Inverse() function is completely wrong.  vsMatrix4x4 * vsMatrix4x4 might be okay.  But I wouldn’t bet my lunch money on it!)