Add new library to mock Rastreio methods

[rubenochiavone]

It would be great if Rastreio class behavior could be mocked to perform testing.

In that way, it could be created a new library inside this project that extends Rastreio class allowing it mock its methods results.

Something similar to mockwebserver from okhttp (ref: https://github.com/square/okhttp/tree/master/mockwebserver).