Merge branch '398-delete_ontology_button' into 701-delete_repository_error

Conflicts:
	app/views/ontologies/_menu.html.haml
allow ontology deletion if the repository is being deleted
put repo delete mark in class instance var
check if onto is imported externally when destroying
add tests for repository deletion
catch ontology delete error when deleting a repository
Merge branch 'staging' into 701-delete_repository_error

Conflicts:
	app/views/ontologies/_menu.html.haml
remove superfluous migration
Merge branch 'staging' into 701-delete_repository_error
fix failing spec: use switched source/target imports
simplify rescue/re-raise StandardError
refactor error message handling
add ontologies controller specs on deletion
add repository controller spec on deletion
move destroying-code into a separate module
fix error in module (forgot included)
use encouraged rspec methods
move class instance variable to module
Merge pull request #751 from ontohub/701-delete_repository_error

701 delete repository error