Stacks-Section: No more HQX

Today I removed all the binhexed files and replaced them with regular compressed files, to save server space. I hope this won't cause any problems for those of you with older Macs, if it does, contact me and I'll work something out.

Also, all pages now sport a change date at the bottom. Note that this may be older than the last modified stack, as it only indicates when the page itself was updated, not when the file archive it displays changed.