refactor getClusterExecutor into Function subclass
push rarely-used repositoryService injection down inheritance tree
refactor Service into a genric interface

simplify node existence checks in AbstractService and delete commented-out code
Checkstyle updates
ignore checkstyle dot files

style conformance in UUIDPidMinter
remove unused RDF type constants and regularize produced serializations
Merge pull request #606 from fcrepo4/80959252

Eliminate dead code

Related to: https://www.pivotaltracker.com/story/show/80959252