Refactored Tree class.

Signed-off-by: Victor Cotrim <cotrim149@gmail.com>
Signed-off-by: Macartur de Sousa <macartur.sc@gmail.com>
Add some test to Tree.t

Signed-off-by: Victor Cotrim <cotrim149@gmail.com>
Signed-off-by: Macartur de Sousa <macartur.sc@gmail.com>
Merge pull request #18 from cotrim149/good_tree

Testing tree structure