Merge all the chell-* subprojects into one repo (2 of 3)

Add 'chell-hunit/' from commit '2fdfaba2c57c3583ca97a5499a77e3e951d7cddb'

git-subtree-dir: chell-hunit
git-subtree-mainline: 461a1b8b10e84f5a3e36672abd1a4a5261aa4c03
git-subtree-split: 2fdfaba2c57c3583ca97a5499a77e3e951d7cddb
tree: 5520c1f625d89a3a53a2acb98e5a13acb9425b84
  1. chell-hunit/
  2. chell-quickcheck/
  3. chell/
  4. license.txt