improve and add inline docs to config page

ref https://github.com/Strider-CD/strider/pull/654

ref https://github.com/Strider-CD/strider/issues/208#issuecomment-64938270

![screenshot 2014-11-29 16 22 04](https://cloud.githubusercontent.com/assets/175305/5234909/0abb88a6-77e4-11e4-9e46-0335723a5bfb.png)