Added/changed some strings and icons.
Added some checks in behavior edition.
Minor UI changes
Changed the widget for toBack and toFront, added in toolbar.
Merge pull request #594 from RotaruDan/SomeImprovements

Some improvements
Improved ImportEntity action to work with frames.
Renamed ImportEntity to ImportEntityResources action.
Renamed ImportEntityTest to ImportEntityResourcesTest.
Also fixed it after recent changes.
Improved RepositoryManager to work with Frames component and nested children.
Added Image Editor to Android external edition tools.
Fixed ChangeInitialScene action target.
Merge pull request #597 from RotaruDan/externalEditionTool

Added Image Editor to Android external edition tools.
Changed DeleteSceneAction to use RemoveRootEntityCommand.
Merge pull request #599 from RotaruDan/initialSceneFixes

Fixed ChangeInitialScene action target.
Merge pull request #596 from RotaruDan/repoManagerImprovements

RepositoryManager improvements
Fixed a bug with FramesComponent that wouldn't reset the frames loop correctly sometimes.
Pictures now have thumbnails displayed correctly.
Also fixed a small bug with the EditionContext after taking a picture.
Merge pull request #602 from RotaruDan/framesComponentFix

Fixed a bug with FramesComponent that wouldn't reset the frames loop cor...
Now MeshHelper also saves thumbnails.
Now painted elements display thumbnails correctly.
Merge pull request #600 from RotaruDan/deleteSceneFix

Changed DeleteSceneAction to use RemoveRootEntityCommand.