Add list tests for replicateA Issue #27
Merge branch 'master' of github.com:NICTA/course
Add zipper function to construct with haskell []. Issue #29
Merge branch 'master' of github.com:NICTA/course
add instance Extend MaybeListZipper. Issue #36
Merge branch 'master' of github.com:NICTA/course
implement instance Extend MaybeListZipper