FMSLogo Code

Inline :d.ang in POLYGONTEST.COMPLEX.
This makes the code simpler, which is good for a regression test.

Inline xexpr.l, yexpr.l, and zexpr.l in POLYGONTEST.COMPLEX.
This makes the code simpler, which is good for a regression test.

Remove "IFELSE :bradius=0" from POLYGONTEST.COMPLEX.
:bradius is never 0, so this was unneeded logic that complicated understanding of the test.

Inline bradius.l in POLYGONTEST.COMPLEX.
This makes the code less general but simpler, which is good for a regression test.

Inline urange.l in POLYGONTEST.COMPLEX.
This makes the code less general but simpler, which is good for a regression test.

Rename rectpoint to POLYGONTEST.COMPLEX.RECTPOINT.
This emphasizes that it's only used by the POLYGONTEST.COMPLEX test.

Inline swap. This reduces the procedure namespace pollution of POLYGONTEST.COMPLEX.

Add some test for special cases for ARCTAN and RADARCTAN.

Cleanup: Remove "atan" and replace it with ARCTAN.
atan had special cases that ARCTAN handles in the same way.
I don't know why this was needed, but it could have been needed when MSWLogo used an old version of Borland's libc.

Combine tzx, xc, yz, and zc into a single procedure rectpoint.
This reduces the procedure namespace pollution of POLYGONTEST.COMPLEX.
This also makes the code clearer, because the four procedures can not be understood in isolation.
It also reduces redundant computation, as the logic of tzx is run once, instead of four times, per point.