add hook for after_retry

[michaelglass]

solution to #29

looks like it might go right around here: https://github.com/y310/rspec-retry/blob/master/lib/rspec/retry.rb#L42-L43

[claptimes5]

Were you thinking this would be some special hook just for rspec-retry or would we run all before/after hooks for each example run? My guess is that we'd want all before/after hooks to run for each retry.

[michaelglass]

so before / after hooks already run so I think this would be before retry.

[elialbert]

not trying to say this is a robust solution, but it is sufficient for my needs:
master...Tiz-team:master