tags: Factor get_tags out of the _get_tags endpoint
tags: Factor get_tags out of the _get_tags endpoint

Gettings a nicely-parsed list of tags is useful internally, so pull
the tag-listing logic out into it's own function.  The decorated
endpoint behind GET /v1/repositories/<path:repository>/tags is *not*
useful internally, so prefix that function with an underscore.

To convert the get_tags iterator to a dictionary, I've used a dict
comprehension [1], which landed in Python 2.7 and 3.0.  I couldn't
find any docs on docker-registry's minimal supported Python version,
so I imagine compatibility with ancient Pythons is not high on the
agenda.

[1]: http://www.python.org/dev/peps/pep-0274/

depay/docker-registry,cnh/docker-registry,GoogleCloudPlatform/docker-registry-driver-gcs,hpcloud/docker-registry,scrapinghub/docker-registry,dalvikchen/docker-registry,dine1987/Docker,OnePaaS/docker-registry,ActiveState/docker-registry,dine1987/Docker,alephcloud/docker-registry,atyenoria/docker-registry,hpcloud/docker-registry,nunogt/docker-registry,atyenoria/docker-registry,cnh/docker-registry,pombredanne/docker-registry,csrwng/docker-registry,ken-saka/docker-registry,shakamunyi/docker-registry,whuwxl/docker-registry,mboersma/docker-registry,fabianofranz/docker-registry,cnh/docker-registry,andrew-plunk/docker-registry,mboersma/docker-registry,stormltf/docker-registry,shakamunyi/docker-registry,dedalusdev/docker-registry,kireal/docker-registry,alephcloud/docker-registry,andrew-plunk/docker-registry,GoogleCloudPlatform/docker-registry-driver-gcs,dhiltgen/docker-registry,kireal/docker-registry,dhiltgen/docker-registry,fabianofranz/docker-registry,depay/docker-registry,Haitianisgood/docker-registry,mdshuai/docker-registry,OnePaaS/docker-registry,yuriyf/docker-registry,docker/docker-registry,csrwng/docker-registry,liggitt/docker-registry,hex108/docker-registry,alephcloud/docker-registry,shipyard/docker-registry,dhiltgen/docker-registry,kireal/docker-registry,hex108/docker-registry,mboersma/docker-registry,tangkun75/docker-registry,Carrotzpc/docker-registry,viljaste/docker-registry-1,ActiveState/docker-registry,deis/docker-registry,dalvikchen/docker-registry,fabianofranz/docker-registry,ptisserand/docker-registry,atyenoria/docker-registry,ken-saka/docker-registry,docker/docker-registry,whuwxl/docker-registry,liggitt/docker-registry,viljaste/docker-registry-1,hpcloud/docker-registry,nunogt/docker-registry,ptisserand/docker-registry,tangkun75/docker-registry,HubSpot/docker-registry,docker/docker-registry,depay/docker-registry,liggitt/docker-registry,shipyard/docker-registry,HubSpot/docker-registry,csrwng/docker-registry,dedalusdev/docker-registry,mdshuai/docker-registry,Carrotzpc/docker-registry,wakermahmud/docker-registry,viljaste/docker-registry-1,dedalusdev/docker-registry,pombredanne/docker-registry,ken-saka/docker-registry,pombredanne/docker-registry,deis/docker-registry,ptisserand/docker-registry,wakermahmud/docker-registry,wakermahmud/docker-registry,scrapinghub/docker-registry,OnePaaS/docker-registry,yuriyf/docker-registry,scrapinghub/docker-registry,deis/docker-registry,Carrotzpc/docker-registry,hex108/docker-registry,yuriyf/docker-registry,stormltf/docker-registry,stormltf/docker-registry,shipyard/docker-registry,HubSpot/docker-registry,mdshuai/docker-registry,andrew-plunk/docker-registry,dalvikchen/docker-registry,Haitianisgood/docker-registry,shakamunyi/docker-registry,ActiveState/docker-registry,nunogt/docker-registry,Haitianisgood/docker-registry,tangkun75/docker-registry,dine1987/Docker,whuwxl/docker-registry