In some cases, copying dataset object, either by passing by value or in
some other pattern can lead to code that will close the same dataset
multiple times (e.g. defer). Or otherwise, code with complicated
handling of dataset cleanup.
Fixes: #30, Closes: #31
- Clones get list of clones (paths) made from given dataset or snapshot
- Get list of snapshots
- Find snapshot (search for snapshot by name in children list)
- IsSnapshot change signature (for simplification, hope it wan’t break lot of code)