Added the capability to also delete processes via piped JSON.

For completeness' sake added also the capability to delete processes with piped JSON (ref. [pull req #273](https://github.com/Unitech/pm2/pull/273)). Also adds a param ('pipe' or 'file') that was missing from CLI.actionFromJson call in CLI.js -> CLI.deleteProcess method after CLI.actionFromJson signature was modified in req #273.