internal/v4: fix meta endpoints

We were printing duplicate endpoints in the /meta list.
Also, when retrieving /meta/any with all meta endpoints included,
it was failing because color was not recognised.
Merge pull request #163 from rogpeppe/072-fix-metadata

internal/v4: fix meta endpoints

We were printing duplicate endpoints in the /meta list.
Also, when retrieving /meta/any with all meta endpoints included,
it was failing because color was not recognised.
internal/router: allow top level meta endpoint list
Merge pull request #167 from rogpeppe/073-router-allow-top-level-meta-list

internal/router: allow top level meta endpoint list

We want to be able to find all meta endpoints without
necessarily inventing an entity id.
add CORS headers on archive endpoint
Merge pull request #164 from jrwren/v4

add CORS headers on archive endpoint

https://github.com/juju/charmstore/issues/146
reenable tests when ES disabled; remove ElasticSearchTestPackage
Merge pull request #171 from rogpeppe/075-reenable-tests

reenable tests when ES disabled; remove ElasticSearchTestPackage

Any package that was using ElasticSearchTestPackage would
have all its tests disabled when JUJU_TEST_ELASTICSEARCH=none.
This avoids that behaviour.