Merge pull request #36 from aschnell/master

- allow to sync ALLOW_USERS and ALLOW_GROUPS to ACL of .snapshots directory
Merge pull request #37 from aschnell/master

- updated requires
Merge pull request #38 from aschnell/master

- generate html links
- StreamProcessor::get_root_id() returns bool
Merge pull request #39 from oniko/pull-requests

- StreamProcessor::get_root_id() returns bool
- extend subvolume instance validity for StreamProcessor.process()
Merge pull request #40 from oniko/pull-requests

- extend subvolume instance validity for StreamProcessor.process()