fix bug when adding previously removed relations
[VersionableBehavior] Fix exception message got toVersion
Merge pull request #717 from cedriclombardot/patch-1

[VersionableBehavior] Fix exception message for toVersion
Support for regexp on different platforms

Fixes #719
slugable behavior - scope column overrides $getter

If scope is enabled the `$getter` variable was overriden by scope column, which causes
```
Fatal error: Unsupported operand types
```
unit test
Merge pull request #722 from auss/patch-3

slugable behavior - scope column overrides $getter
Update SluggableBehavior.php
Merge pull request #716 from havvg/hotfix/collection-add-removed

fix bug when adding previously removed relations
Merge pull request #721 from auss/patch-2

Slugable behavior - support for regexp on different platforms