implemented osm and leaflet
added new app playgrounds
added model of playgrounds
added json2geo.json script and copy school app code to playground app ;)
added json2geo.json script and resulting geo.json formated playgrounds
customize load_playground_data
improved json2geojson.py and geo.json file (local_traffic key)
created the loader for playgrounds, connected with /api-url, all other except local_traffic works fine, added loader to makefile
fixed model for stops and lines
added some libs to requirements
Delete json2geo.json
Delete load_school_data.py
Merge branch 'master' of https://github.com/CodeforLeipzig/kidsle into DjangoFrontend

# By Max Brauer
# Via Max Brauer
* 'master' of https://github.com/CodeforLeipzig/kidsle:
  formatted playgrounds.json and added lat/lng
  added playgrouds.json
made markers for playgrounds and kitas visible on the map with custom markers
made layergroups for users to toggle markers
yeah filter workes in custum menu
updated color for palygrounds and replaced checkboxes by buttons
added leafletmarkercluster js but there seems to be a problem with the playground layer. there ist a duplicate of each item
- removed json2geojson script - not necessary anymore
- removed PyYAML because only json2geojson needed it
- deleted json2geojson
- added model for playgrounds