provide more failing information for entity-spec.
Handling of Sidekiq::Shutdown

Set the state to pending, because sidekiq requeues the current job.
Closes #340 and #430
Merge pull request #451 from ontohub/hotfix_entity_spec

Hotfix entity spec
add database-cleaner to rspec.
fix database cleaning method for rspec.
Sidekiq and Sidetiq updated
adjust import_xml_from... parameter order in spec.
deactivate stub after use.
Merge pull request #457 from ontohub/augmenting276_add_descriptions_to_symbols

Fix testing problems for described symbols
Merge branch 'augmenting276_add_descriptions_to_symbols' into develop
Rails updated
add obo (and others) to hets-supported file etensions. fix #459
Merge branch 'staging' into develop
Merge branch 'develop.ontohub.org' of github.com:ontohub/ontohub into develop.ontohub.org
Merge branch 'develop' into develop.ontohub.org