Merge pull request #127 from stonaz/master

Open 311 Discovery service + Open 311 web ui refactoring
Open311 settings.example.py indentation cleanup
nodeshot.core.nodes API: use slug instead of layer ID
UI: reflect API change (slug instead of id) in UI
UI: toggle specific layer data from map
Merge branch 'master' of https://github.com/ninuxorg/nodeshot
Open 311 interface restyled