Merge pull request #5 from OwnWaterloo/master

thanks! merged!
typo: but
Misunderstanding about Haskell:

* Has non-strict semantic(http://www.haskell.org/onlinereport/intro.html).
* Has type signature(http://www.haskell.org/onlinereport/decls.html#type-signatures)
  as well as type inference.

  IMHO, the following statement
  "you make some slight change to the implementation, ... , the interface change, and every thing has to change."
  is misleading.
typo: actually