This commit prepares the frontend code to be consumed by webpack.
It is a hack: In theory, modules should be declaring and importing the
modules they depend on and the globals they expose directly.
However, that requires significant per-module work, which we don't
really want to block moving our toolchain to webpack on.
So we expose the modules by setting window.varName = varName; as
needed in the js files.
The slash in command is stripped in the backend,
rather than in the client to make the client code
cleaner.
This would make client code cleaner in the slash
commands which include parameters.
These two slash commands now use zcommand to talk to
the server, so we have no Message overhead, and if you're
on a stream, you no longer spam people by accident.
The commands now also give reasonable messages
if you are already in the mode you ask for.
It should be noted that by moving these commands out of
widget.py, they are no longer behind the ALLOW_SUB_MESSAGES
setting guard.
This adds a /ping command that will be useful for users
to see what the round trip to the Zulip server is (including
only a tiny bit of actual server time to basically give a
200).
It also introduce the "/zcommand" endpoint and zcommand.js
module.
Cynthia Lin
Armaan Ahluwalia
Rhea Parekh
Steve Howell