* Bzip2 was manually installed directly into filesystem, so bzip2 package was empty.
Fixed by installing it to destdir. bzip2 moves out its binary before installing
its own package.
* sha256sum from stage0-posix was not checking any checksums because it does not
accept piped input. Fixed by using temporary file.
* grep was broken for a short time (but with fixed bzip2 package this caused failures)
due to touch creating grep file of zero size (egrep symlink was touched).
Fixed by implementing touch -h
Resolves#156, resolves#166, resolves#167
