Create manpages for the project

This commit creates the manpages for the project.  There are two
versions implemented here: the en_US, and the pt_BR.  Along with the
manpages, I am also modifying and creating Makefile.am files needed to
properly handle/install the manpages.

It is worth making some notes here:

- We have to keep an eye in order to sync the manpages every time one of
  them is modified.

- We also have to be careful to update the manpages every time a new
  option is added to the program.