Backport some changes from my fork (for intermediate tag/release)
Update the Docker plugin
Merge remote-tracking branch 'origin/master'

Conflicts:
	roboconf-iaas-docker/src/test/java/net/roboconf/iaas/docker/IaasDockerTest.java
	roboconf-plugin-puppet/src/main/java/net/roboconf/plugin/puppet/PluginPuppet.java