Add the ability to listen to streamers

[benjivesterby]

Define an interface which looks similar to this

type streamers interface {
    Events() <-chan interface{}
}

That can be registered into the alog system. There should be the ability to have 0-N of these registered and alog should pull events from them and log them to the appropriate destinations based on their interface types.

Internal interface types for it to recognize would be initially error and stringer which would go to the Error and Print methods of alog respectively. This should be extensible in the future to be able to add additional error types. This registration system should be able to use the same c method types which accept interface types.