Support ability to add multiple transports of same type

[tfulton]

Right now, it does not seem possible to add multiple transports of the same type. For instance, I would like to add multiple "winston.transports.File" transports, each with a different level -- in order to create separate files for each level logged.

If this is not supported, is this something that has been considered?

[barisusakli]

👍 Not sure if this is possible with the current system.

[arthurblake]

I am surprised that it doesn't work this way already. Seems like a very basic logging need -- that a transport is decoupled from the logger (just like an event listener) where you can add as many as you like.

[indexzero]

Duplicate of #101.