Load files from multiple directories. Currently some files are duplicated in different dirs, uncomment check when that is sorted.
Fix exception handling for biosamples
Raise errors on duplicate found files.
Merge branch 'master' into testing-improvements

Conflicts:
	src/encoded/tests/test_views.py
Data fixture tweaks.
BDD pytest plugin. Features now load a data fixture with usefixtures.
Finish test refactoring