Fixes https://github.com/octobercms/october/issues/245
Fixes bug in validation, remove redundant BelongsOrMorphToMany trait
Merge branch 'develop'
listsNested and getNested will apply orderByNested() automatically to prevent confusion
Fix to sluggable trait
Update File.php

Added "offset" option to getThumb()
Update Resizer.php

Added "offset" options to resize() and crop()
Update Resizer.php

Added ```@param array $offset The offset of the crop = [ left, top ]``` to both the resize() and crop()
Merge pull request #18 from DanielHitchen/master

[Feature Request] Added "offset" to getThumb() options
Deprecate NestedSetModel.php and TreeModel.php
Extendable construct now comes before Trait booting
Use a global scope instead of applying the order in the logic
Add option to TreeCollection to remove orphans