Radiance 3.4 release

Good point about using the mixpict primitive -- I vaguely remembered programming something like this, but then didn't see it in the ray.html reference manual, so I thought I must have dreamed it. I guess it's one of those things that didn't get updated when it should have because I wasn't sure that it was in the LBNL release or not. Now that it's there in 3.4, I went and updated the HTML reference manual, but I know there are still a lot of man pages on the website that are in need of updating... Unfortunately, I don't have any of the tools I onced used to convert nroff into HTML and PostScript. Sigh. Guess that's something to do in my "free" time. If something seems inconsistent, it's best to rely on what's in ray/man/man1 in the 3.4 distribution.

I just compiled 3.4 for SGI machines, since most systems come without a compiler license these days. John Mardaljevic also reminded me that there is a problem getting the TIFF library to compile under Solaris. The "install" program on some Solaris systems seems to be broken, so the TIFF library fails to install properly, and the rest of the programs in the src/px directory don't get installed as a consequence. This can be remedied by manually installing the library from src/px/tiff/libtiff into src/lib, but it's too bad I don't know of a better fix than this.

I'm still planning to compile under Intel Linux, and will probably get to that in the next day or two. If Lars beats me to it and sends me the binaries, so much the better!