bubble sort (4teach)

bubble sorting visualization (4teaching).
inspired on http://wonderfl.net/c/8rbD
thanks to Ms. Fabiana C. Guedes.
Universidade Federal de Itajubá - Campus Itabira
git https://github.com/thyfl/eco-010/tree/6649fa0593d1e2e31f37e8440123a048146d8fba/fabiana/extras/bubble
@author thi