First draft of a solution for #1375
rosie go: co update not working
rose.config: support optional opt conf keys
Document optional opt conf keys
rosie go: hover over changed, incomplete
Fix an issue with rose-ana where it believes files in the app's file directory are tests
rosie go: hover over for local status update
Merge pull request #1398 from scwhitehouse/rose_ana_file_fix

Fix an issue with rose-ana where it believes files in the app's file directory are tests
Merge pull request #1399 from kaday/rosiego_co_hoover_update

Rosiego co hover update
rosie.ws_client: support multiple sources

`rosie.ws_client` is modified to work with multiple prefixes.
Use `multiprocessing.Pool` to send requests to the sources in parallel.
This requires a pickle-safe version of python-requests.

The `--prefix=PREFIX` for `rosie go`, `rosie lookup` and `rosie ls` can
now be specified multiple times. The lookup mode is rationalised into a
single option, with aliases.

`rosie go` updated to allow users to select any data source combination.

`rosie.suite_id`: The logic to obtain other user's local copy root is
not ideal, but there is no easy way to make it more general, so accept
that we hard code at the moment.

Tests:
* t/rosie-ls: new basic tests.
* t/rosie-lookup: new basic multi sources tests.

Other changes:
* Refactor.
* Pass `pep8` for modified modules.
Update version requirement for python-requests
rosie refactor: update date format, doc, etc
Fix tests
Merge pull request #1397 from matthewrmshin/optional-opt-conf-key

rose.config: support optional opt conf keys
rose.config_tree: improve pep8 and pylint scores
rose.config_tree: store file lists

If a relative path can be found in 2 or more locations in the linearised
inheritance, it will store the configuration locations in a new list.
Use rose.config_tree to load metadata

Part 1.
rose.macros.trigger: use rose.config_tree

to load metadata.
Merge branch 'master' into refactor-rosie.ws_client
Update CHANGES.md