Made createId use boost::uuid, removed check for uniqueness

Also adapted tests
make id boost::uuid & small fixes:make refs const,group methods faster
Merge pull request #348 from balint42/boost_uuid

Made createId use boost::uuid, removed check for uniqueness

LGTM
Implemented operator=(none_t) on frontend entities as in issue #352

Added all missing tests too
Implemented nameSanitizer util function
Merge pull request #353 from balint42/operator_none

Implemented operator=(none_t) on frontend entities as in issue #352
Implemented use of nameSanitizer on group-level
Merge pull request #355 from balint42/sanitize_name

Sanitize name