Describing memory spooling in combination with console command

[Sgoettschkes]

As discussed (symfony/swiftmailer-bundle#23), when memory spooling is active and one tries to sent mails from a console command, nothing happens because the kernel terminate doesn't get called.

I tried to find a good place and think the email cookbooks are ok. I didn't want to put it with the console documentation as the console is a stand alone component and the docs are written in a general way. The behaviour described above on the other hand is related to how symfony works with the events.

[stof]

We already added a cookbook about emails in the CLI

[stof]

ah no sorry, it was about links

But this should be a cookbook article, not a note in the book.

[Sgoettschkes]

I realized there is a console cookbook. I think this would be a good place to make a dedicated article describing the handling of emails within a console command. I think I can find some time this week to write it and will do another pull request.