Worked on loading, Space, Cell.

Added a few helper methods to Json.
Changed Spaces for subclasses to hold type instead of just returning
correctly. For serializing. (Didn’t change interface)
Uncommented developerPlayer from Cell, serialized it.
Merge branch 'master' into mauricio
Added JsonObject

JsonObject holds a map<String, Object> to hold the complete subtree of
loaded game.
Changed Serializable interface and all users

Changed the loadObject(String serial) function in serializable to
loadObject(JsonObject json).
Changed all implementing classes too.
Merge branch 'master' into mauricio
Merge branch 'master' into mauricio
Merge branch 'mauricio'