dm-2

PT-2080 Add JSON logging to pt-kill

6

### Problem Currently, `pt-kill` provides two logging options: 1. Plain text output to stdout/file ([source](https://www.percona.com/doc/percona-toolkit/LATEST/pt-kill.html#output)): ``` # 2009-07-15T15:04:01 KILL 8 (Query 42 sec) SELECT * FROM huge_table ``` 2. To...