Change the behavior of template option

This PR addresses https://github.com/AIFDR/inasafe/issues/854

The new UI
![new options](https://cloud.githubusercontent.com/assets/992519/2692279/c074a8a8-c39e-11e3-96fa-41069fcc9659.png)

@timlinux: 
- There are some variables that are referred by some classes which I think it should be put as a default e.g the default of organisation logo path (referred by dock, report, and option dialog), or north arrow (reffered by report and option dialog). Should we put it like disclaimer on safe_qgis.utilities.default?
- I thought the report template directory option will override the default directory. After looking at the code, it turns out that it will add all the templates inside, so I give the text for that option as "Add report templates directory."
- There is no failing tests related to this change.