Add solutions for chapter 5.

@fabioyamate, @laurocaetano I'm so sleepy that I don't remember where I had to change on the last exercise, haha.
from you experience, it is more common to use the `$` application or `()`? Are there cases where one in preferable than the other?

comparing with this one: `toUpper (shift n (toLower c))`

with `$` it seems to be cleaner than with `()`