This is a pure refactoring that mostly just moves code from
subs.js to the new stream_color.js and updates module references
accordingly. In order to prevent introducing some exports,
update_stream_color was given an additional "sub" parameter
and update_stream_sidebar_swatch_color was given an "id"
parameter.
Killed off unused initial_color_fetch var.
(imported from commit b7644ce67f50d31fb46f564d758d661eea776aa6)
In the future, this could come from the server to enable individual
experiments on a per-realm basis.
(imported from commit 8fd1ba1910b3cfd131f58bab8efbd11a42053bc3)
Steve Howell
Tim Abbott
Kevin Mehall
Scott Feeney