Detect logs using euro timezones

[David Arango]

Right now the Rails and Clf detectors only work with logs using timezones minus GMT. For example the Rails regexp catches this time:

2012-09-01 09:34:35 -0400

But not this other one:

2012-09-13 21:30:58 +0200

Easy to fix, I could have done a pull request, but since this is a small fix I think an issue is enough :)

Nice job!