added mailer component

Added Mailer component, wrapper over SwiftMailer.
Because at first quite all namespaces in Phalcon where about things they were working with : Assets, Models, Events, ...
The manager is an Assets manager or a Models manager ... The namespace naming is logical
So having something which manage mails (creates them, send them, (and perhaps parse received one ?) should be named (in my point of view) Mails\Manager

Now we have Translate and Logger namespaces, i don't like this as it's not the same point if view, for loggers, i would have prefered a Logs namespace and a Translations one. @phalcon what do you think about this ?

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