Restructure preload data into a JSON-friendly format

This allows using the same preload data both from JS and Java
Put preloadData.js back to the proper location
Lookup by string id instead of integer
Load data from different backends based on host
Merge branch 'master' into gae
Add city to Course
Initialize datastore using preloadData.js
Send pars as int instead of long
Send pars as int instead of long
Ignore .DS_Store files