Proper handling of octagonal and square pins

[dkogan55]

Prior to this patch, the square-pin geometry functions were incomplete, and the octagonal-pin geometry functions were almost completely missing. What little there was was buggy. I'm attaching 2 patches that hopefully handle all of the possible geometrical intersection possibilities to support square and octagonal pins. I'm also attaching a .pcb file I used to evaluate the code, but more tests are desireable. To test, press 'f' to check for geometric intersections of the components. I was not 100% clear on what "bloat factors" are, so it is possible that some parts of these patches neglect those.

[Peter Clifton (pcjc2)]

Just a minor nit, PCB / gEDA in general uses /* */ comments, not //

I think eventually the way forward to support any non-round pin type is to use arbitrary polygons for the intersections.