feature added -t option to measure task excution time (#61)

[kattakaha]

Summary

I have implemented a solution for issue #61 (ref: https://github.com/taskipy/taskipy/issues/61) which has been inactive for a while and also relevant to my own needs.

Details

To prepare for future options using decorators, I have enhanced the runner by allowing it to receive a list of decorators. This enhancement supports an option to display the task name and measure the execution time with either -t or --time.

Screenshots