retry - backoff strategies for Go

The retry package implements a handful of backoff strategies that use the technique described in http://blog.gopheracademy.com/advent-2014/backoff/ . This package API is finalized and should only see backwards-compatible changes (perhaps an additional backoff strategy or two).

API documentation can be found at http://godoc.org/aqwari.net/retry. Issues may be opened at github.com/droyo/retry.