[LTP] new shell library

[Cyril Hrubis]

Hi!
I've played bit with the shell test library in order to make it more
aligned with the C library, have a look at:

https://github.com/metan-ucw/ltp

So far I've converted all testcases in commands/ directory, you can have
a look at last 12 commits in the repo to see how the new shell library
and testcases looks like. I would love to get someone to review the code
before I attempt to convert more testcases.

-- 
Cyril Hrubis
chrubis@suse.cz