Nick Becker's Timer Assignment

Submitting Nick Becker's timer.py assignment
I am interested that you choose to return self.start here.  I see nothing wrong with it, but what do you imagine someone would do with that value?  It'd be used like this, I guess:

```python
with Timer() as start:
    print "we started at {}".format(start)
    # do some code stuff
```

But I have a hard time imagining the value of that.