Allow REST server to be shut down remotely

[Tristan Croll]

I'd like to suggest the following patch to bundles/rest_server/src/server.py allowing the server to be gracefully stopped from the client side. As it stands, sending the command:

http://localhost:{port}/run?command=remotecontrol rest stop

hangs both the client and ChimeraX itself, since it shuts down the server *before* returning a response. The patch allows the command:

http://localhost{port}/stop

... which sends an acknowledgement to the client first and then shuts down the server.

The current use case is that the Phenix team want to be able to query ChimeraX to see if ISOLDE is installed/up to date (and bring up a dialog on the Phenix side asking if they want to install/upgrade it) before starting ISOLDE's own REST server. The simplest way I can see to do this right now is to first run ChimeraX's built in server to query the list of installed bundles and do the installation if necessary, then start ISOLDE's server on a new port and shut down the ChimeraX one.

[Conrad Huang]

Fixed in 3c9d3446e.

Instead of adding another special URL, I changed the server code so that a stop request will wait until all running requests finish before shutting down the server. So "remotecontrol rest stop" should work as expected rather than hang now.