Use "base64 --decode" instead of "base64 -d"

This is another OSX-specific bug.
Move libraries before binaries

I believe this is the correct ordering for a Configfile (and I guess I
should know that, seeing as how I wrote it!).
Test harness improvements for OSX

This has the side-effect that valgrind won't be run on systems that
don't have it, which is probably a good thing.
Use library extensions whenever linking

This makes it more apparent that the cached files in obj/ are really
just copied into lib/.
Call .so files .dylib on OSX

Of course, Apple had to be different.
Work around Apple's odd rpath semantics

I have no idea why Apple does it this way, but it seems to at least be
somewhat working now.
Join STDOUT and STDERR in ptest tar

This makes reading the output of tests a bit easier.
Add sleeps in test harness

I believe the problem is that I'm running the touch command too close
to the previous make command, which is causing the modified file to
have the same mtime as the unmodified file.  This causes problems on
systems with looser filesystem resolution.

This has been by just sleeping a bit so the modifications are farther
apart.