Framework: Fire events for artisan commands

[freezy-sk]

It would be fine when we can hook on some Artisan events when they are fired with corresponding command name. For example call, execute, run for db:seed should be artisan.call.db.seed, artisan.execute.db.seed etc.
It's all about adding few lines into Illuminate\Console\Application and Illuminate\Console\Command.

[crynobone]

Would prefer something standard such as artisan.firing: command:name

[GrahamCampbell]

We're open to pull requests.