removed 'start_node = Neoid.db.get_root' in NeodatabaseCleaner because latest neography get_root function is broken, and NeodatabaseCleaner.clean_db() does not need start_node attribute'
Merge pull request #36 from minsikzzang/master

removed 'start_node = Neoid.db.get_root' in NeodatabaseCleaner