message: make docker hub links point to docker hub readme
diff: @@ -11,7 +11,7 @@ Current Build Status
  - Linux and OSX: [![Build Status](https://travis-ci.com/opcm/pcm.svg?branch=master)](https://travis-ci.com/opcm/pcm)
  - Windows: [![Build status](https://ci.appveyor.com/api/projects/status/github/opcm/pcm?branch=master&svg=true)](https://ci.appveyor.com/project/opcm/pcm)
  - FreeBSD: [![Build Status](https://api.cirrus-ci.com/github/opcm/pcm.svg)](https://cirrus-ci.com/github/opcm/pcm)
  -- Docker Hub: [![Build status](https://img.shields.io/docker/cloud/build/opcm/pcm.svg)](https://hub.docker.com/r/opcm/pcm) [![pulls](https://img.shields.io/docker/pulls/opcm/pcm.svg)](https://hub.docker.com/r/opcm/pcm)
  +- Docker Hub: [![Build status](https://img.shields.io/docker/cloud/build/opcm/pcm.svg)](https://github.com/opcm/pcm/blob/master/DOCKER_README.md) [![pulls](https://img.shields.io/docker/pulls/opcm/pcm.svg)](https://github.com/opcm/pcm/blob/master/DOCKER_README.md)
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  PCM Tools
  