Bump to 0.0.5.1

Fix TimeMeter to track a counter value and return time per unit count. (

pytorch#123)

* Fix TimeMeter to track a counter value and return time per unit count.

Even though the documentation states that TimeMeter returns the time passed since the last `reset()` divided by the counter value when `unit=True`, this was not actually the case. This fix updates the code to do what's described in the documentation.

* Clean up whitespace to pass flake tests.

* Raise error if trying to divide by zero in TimeMeter.

deploy from master