make fill_polygon accept floats

[baloe]

Right now mahotas.polygon.fill_polygon requires input points to be integer-typed. That's quite restrictive.

[luispedro]

I actually agree. The code does work with integer-valued inputs, though.

[baloe]

I don't actually know the code behind fill_polygon, but I was wondering: fill_polygon probably considers the actual (float-valued) locations along the polygon lines, does it not? In that case it seems like a low-hanging fruit to also enable float-valued coordinates for the description of those polygon segment end point nodes.

I ended up using skimage.draw.polygon, which solved the problem for me. So feel free to close this issue.