Catch errors

[mendaxi]

When you run bitmessage from the command line, there is a stream that shows log events.
There should be a process like #34 that catches all error and critical events, then optionally sends them in a bug report.

[PeterSurda]

You already can configure log handlers, it just isn't well documented. The ability to send a report on crash sounds nice, but I worry it will be too much work at the moment. I'll look at it during the 0.7.x cycle.