sanitize invalidly named FS paths

partially reverts 34748dda
add API doc note about /-separating fileset entries
Merge remote-tracking branch 'remotes/origin/develop' into trac-11625-sanitize-file-paths
Merge remote-tracking branch 'remotes/origin/develop' into trac-11625-sanitize-file-paths
Merge remote-tracking branch 'remotes/origin/develop' into trac-11625-sanitize-file-paths
Merge remote-tracking branch 'remotes/origin/develop' into trac-11625-sanitize-file-paths

Conflicts:
	components/blitz/src/ome/services/blitz/repo/ManagedRepositoryI.java
Merge pull request #2909 from mtbc/trac-11625-sanitize-file-paths

fix #11625: sanitize invalidly named FS paths