gonotes: enumerate annotations in a go source tree

gonotes.md

Spec for a tool to enumerate annotations in Go source tree.

$ gonotes -markdown

TODO
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1. Add acceptance testing to vagrant builder
   21: go.ovrclk.com/walker/agency/builder/builder_test.go

2. Remove 100 zones limit
  220: go.ovrclk.com/walker/farms/namer.go

FIXME
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1. IP CIDR range predictions fails on a race condition
  45: go.ovrclk.com/walker/clusters/service.go