Refactor data types for core integration

- Refactored Map to inherit from MapObject
- Created Drawable object, which defines how to translate a core object
into a drawable
- Temporarily disabled all user management features (one feature at a
time)
Fix issue regarding padding for bounding rectangle
Fix issue regarding placement of beacons on canvas
Implement ToString for core data objects
Migrate Bridge to new server

- Object Ids are temporarily public in order to resolve an issue with
JSON deserialization