Add support for Log::Log4perl

[pjf]

Log4perl is utterly brilliant, and fits well with the exobrain methodology of being able to dynamic react to things. (You can change logging options on the fly for running processes.)

We should move Exobrain over to using it, as it's much nicer than our quick'n'dirty logging with Ubic.

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[techman83]

I've made a bit of a start with Exobrain::Logger and a script that watches the Bus. It's been running nicely on my instance for a while.

Is there a list of things we want from it? I've been pondering it for a little while. I'll have a think about it as I write Exobrain::Strava.