Introducing MF2_LINKDRAW! I put it in this branch because it (ab)uses some...

Introducing MF2_LINKDRAW! I put it in this branch because it (ab)uses some structural changes I made for papersprites.

* Sets the sortscale of the mobj to that of its tracer.
* Basically, Smiles' tails won't clip through shields thanks to this.
* http://gfycat.com/GraveGlassEwe
* Also has support for chains of MF2_LINKDRAW!