Ported ST and Writer examples.
Merge pull request #353 from folone/scalaz-seven

Ported ST and Writer examples.
maximumOf/By and maximumOf1/By1 methods for Foldable(1), plus Foldable(1)Test
tuned
Running a free monad in another monad.
Handy for turning trampolines into futures.
tests for `MinVal` and `MaxVal` semigroups

Contributed in #356 by @oxbowlakes
Merge pull request #354