WIP 0.11.0
update dashboard core to use app_settings package when available. #89

Only fetches entire ddoc when app_settings paths are not found.

One fetch of a ddoc is still required right now during settings
migration.  The settings migration path is specified in the `kanso` or
`couchapp` property of the ddoc. We should consider extending the
app_settings module to allow for querying abitrary properties on the
ddoc.
never push to market on PRs.
refactored app update in dashboard core #89

made ddoc fetch during migration optional.

added `has_app_settings_support` function that does a HEAD
requests.  This adds a few additional requests during install
but makes code cleaner.

`migrate_app_settings` function ddoc parameter was removed, is was never
really required in the first place, all we need is the migration path
there.
Merge pull request #91 from garden20/develop

support app_settings during updates/install