With this change manager will run reproduction on crashes
until reproducer is discovered, but at most 3 times.
If reproducer is discovered it is saved with crashes and shown on the web UI.
Infinite verbosity produces too much noise, so don't cache messages with verbosity>1.
Need something better later, e.g. ability to view messages for different verbosity levels.
Log is a simple wrapper around std log package.
It is meant to solve 2 main problems:
1. Logging from non-main packages (mainly, vm/* packages).
Currently they can either always log or not log at all.
But they can't respect program verbosity setting.
Log package allows all packages to use the same verbosity setting.
2. Exposing recent logs in html UI.
Namely we want to tee logs to console and html UI.
