Admin service gui


This pull request contains a simple UI for adding and configuring stages.

Currently it can only add and update one stage per stage-group.

Changes to the Admin Service REST API:
* `stagegroups` now does library files inspection, meaning it will take the same amount of time (or more) than the `libraries` endpoint to return. On the other hand, you get the description, required-flag and current value for all properties.

![0-admingui-stagegroups](https://f.cloud.github.com/assets/1385872/2169649/e1c2b906-955d-11e3-875c-ebb6549a373b.png)
![1-admingui-stagegroups-modify-stage](https://f.cloud.github.com/assets/1385872/2169650/e39eb766-955d-11e3-9cf4-c786f9af2221.png)
![2-admingui-libraries](https://f.cloud.github.com/assets/1385872/2169652/e949c62e-955d-11e3-84c4-b622585ccdb0.png)
![3-admingui-libraries-add-stage](https://f.cloud.github.com/assets/1385872/2169654/eb04a506-955d-11e3-8eb6-c1a1e0ff3d7a.png)