Decoupled result and reporter in `pyvows.cli:run()`
Renamed `handle_{success,error}` to `on_vow_{success,error}`

The original name made it tricky for me to understand what the class method was actually for.

Finally, my brain clicked, and I understood. It’s basically a hook for each vow’s success/error event.

As such, I renamed these (and references to them throughout PyVows) to more accurately reflect their purpose.
Merge pull request #80 from Zearin/misc_cleaning

Minor code cleaning