change fixture_file ontology-call to ontology_file.
Merge pull request #1112 from ontohub/fix_fixture_calls

change fixture_file ontology-call to ontology_file.
move persisted? method to fakerecord
simplify target_path
add RepositoryDirectory FakeRecord
Add view for RepositoryDirectory
add DirectoriesController
Fix target_path methods (leading slash not allowed)
fix validation in RepositoryDirectory
activate directory creation
add comment on class purpose
use more delegates, remove redundant code
simplify committing mechanics
configure rspec mocks
fix specs on ontology deletion
sort directory listing by downcase name
fix empty repository !present? error
fix Repository#path_exists? on empty repository
add factory for RepositoryDirectory
add validation specs