Change ENA ontology to ENA_test in populate.sql
Default to load ontologies, needed for interface

But do not load ontologies in travis, since they are not needed for general
testing
Add _investigation_type_ontology to PrepTemplate

This allows for testing with alternative ontologies (required when using
a test environment and --load-ontologies is passed to `qiita_env make`)
flake8 fix
Add comment explaining instantiaion in classmethod
Merge pull request #591 from adamrp/fix_test_env_ontologies

Change ENA ontology to ENA_test in populate.sql