Since in the future we might want requests to add subscriptions to
include things like colors, in_home_view, etc., we're changing the
data format for the add_subscriptions API call to pass each stream as
a dictionary, giving a convenient place to put any added options.
The manual step required here is updating the API version in AFS
available for use with the zephyr_mirror.py system.
(imported from commit 364960cca582a0658f0d334668822045c001b92c)
58f4ffe088