EngineObject system
Clarified some names and some concepts:
- Schema object to refer to objects in the model
- Engine object to refer to the representation of the schema in the engine
Merge pull request #2 from anserran/engineobjects

EngineObject system
Merge pull request #6 from anserran/scenemanager

Added simple engine tech demo
Original message (aserran):
Added an engine tech demo with a minimal game.
Also, corrected a bug while reading scenes resources
Updates in schema IO
- Renamed JSonIO to SchemaIO, since this class ONLY read json representing schema
- JavaDoc added for related classes updated
- Added tests to test serializers
Merge pull request #5 from anserran/schemaio

Updates in schema IO
Work in progress
Added test to scene manager