Notion of edition context added to model
Updated selectioncommand to set contexts
Updated set selection action.
Added set edition context action
scene listener uses setEditionContext action
AddSceneElement uses context as parent of the added entity
Edit scene updates the edition context
Move WalkComponent to components
Merge pull request #539 from anserran/contexts

Added notion of edition contexts
Merge pull request #544 from manuel-freire/move-walkcomponent

Move WalkComponent to components
Small Scenes bugfix.
Improved EditorGameAssets#resolve(String) method
EditorGameAssets now loads engine skin.
Remove static reference in CommandTest
- addComponent moved from EntitiesLoader to ComponentLoader and made public
- AddComponentExecutor now uses ComponentLoader.addComponent instead of creating components by itself
Accommodating to changes in API
Merge pull request #556 from jtorrente/fix-514

Fixes #514
Merge pull request #548 from RotaruDan/fixes

Small Scenes bugfix.
Merge pull request #549 from RotaruDan/editorAssetsSkinLoading

EditorGameAssets skin loading