Add option to use stages for the repo setup instead anchors

Requested in Issue #157
Merge pull request #159 from elasticsearch/repo_stage

Add option to use stages for the repo setup instead anchors
Update files for release 0.5.1
fix inline docs
fix typo in docs

Closes #160
Update proxy config and run apt-get update after docker container is booted
Modify check for port validation
[TESTING] Increase retry times and delay time

On slow / loaded systems the startup can be a bit slow.
This should avoid the false errors
[TESTING] Remove port check

the port check has been causing allot of testing issues.
For now the basic tests are fine.
[TESTING] Make use of new centos image
Merge pull request #163 from elasticsearch/new_centos_image

[TESTING] Make use of new centos image
Add check for listing all logstash processes
Fix typo
Messed up the test
Remove failing tests