oauthclient: get token fix

* Fixes an database query issue causing several tokens to be returned
  which in the end results in a token not belonging to the user could
  be returned.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>
utils: PEP8 fixes

* Fixes PEP8 errors in DataCite module.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>
pidstore: admin interface

* Adds initial admin interface to persistent identifier store.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>
admin: registry discovery

* Changes admin discovery to use Flask-Registry.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>
formatter: output format/elements loading fix

* Fixes loading order output formats and format elements to respect
  loading order of packages.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>