Increase test coverage to 95%

[diegozea]

Actual test coverage is ~89%. That's great! However, would be great to increase that number to make this package more reliable and avoid future regressions ;)

It's easy to see what lines are missing tests using codecov and coveralls.

We need to find a way to test MIToS.Utils.Scripts and plot recipes. Also we need to test more Base.show and Base.print (example to test show).