Stopwatch functionality.

By default show time/memory consumed by fix process.
With verbose option show time per file as well.

It helps keeping in mind performance. At least for me.
All other places in FixCommand check verbose by getting an option, not by `getVerbosity` method. It could be a good change - and it deserves a separate PR. Keep PR atomic.

IMO it should be printed due to verbose, not debug. It is so small output change to introduce separate option for it.
Should we use very verbose? We print which files was modified without verbose option, which fixers was used on files with verbose option, so IMO we could show times spending on files with verbose, not very verbose.