isometric: rewritten to use the new rframe xforms from libgeometry.
isometric: fixed the RFrame transformations.
made it work with the current libgeometry provided by the system.
mkfile: use the system-wide libgeometry.
ptinpoly: fix colors and polygon countour.
draw a proper set of axes using a naïve method.
ptinline: the user sets the line. fixed coordinate input.
import the utilities from the isometric toy.
isometric: draw tall tile sprites and change the map in real time
bsplines: can't make one without at least three points