The Coding 40° group members write their programs together. So, this
code is result from a well shared work.

pev main author is Fernando Mercês.

Coding 40° group members:

Eduardo Fernandes <eduardoffs@gmail.com>
Fernando Mercês <fernando@mentebinaria.com.br>
Francivan Bezerra <fba.rio@gmail.com>
Thiago Moraes <moraes73@gmail.com>

Thanks to Evan Teran <eteran@alum.rit.edu> and
Gabriel Duarte <confusosk8@gmail.com> for help.
