Merge pull request #5 from AlekSi/master

Unlock Registry mutex even in case of panic
README fixes.
Add metrics.DefaultRegistry so there's an easy way.
Shorter Graphite emitters.
Use a net.TCPAddr instead of a string in Graphite.
Add a prefix to Graphite metrics.
Add UpdateSince for use with defer.
Update the Timer interface for Go 1.
Friendlier CaptureRuntimeMemStats.
Always fetch fresh stats.
New stats in Go 1.
Style upgrade.
Way more correct PauseNs.