Adding a "documentation" component that has a name property. This component is added to the scene when it's created through Templates
Fixing AddScene: it was creating a FieldCommand with model.getGame() instead of using Model.getComponent(model.getGame(), EditState.class)
Fixing FieldNames. It contained several missing references.
Also: FieldNames has been moved to editor-schema. This allows us to reference the class in Exporter
Refactoring RenameScene and Rename actions. Also RenameTest has been updated and now it compiles and runs well.

Note: Rename still needs refactoring to comply with latest action refactorings, but it's better to do that once all tests are back up and running again.
- Rename.objectHasName simplified
- Minor formatting issues
Merge pull request #336 from jtorrente/documentation-component

Documentation component + other stuff