Add __repr__ and __str__ methods to ParentList
Add __repr__ and __str__ methods to ParentList

It makes development and debugging easier and makes output of
device.parents and device.children (which is a simple list) same.

vojtechtrefny/blivet,vojtechtrefny/blivet,rvykydal/blivet,rvykydal/blivet,jkonecny12/blivet,jkonecny12/blivet