atexit won't run registered functions for SIGTERM which we send to the server.
This prevents clean shutdown.
Also making sure that the server logfiles are deleted as well.
Now, every FileReadyToParse event returns diagnostics, if any. This is instead
of the previous system where the diagnostics were being fetched in a different
request (this caused race conditions).
There appear to be timing issues for the diag requests. Somehow, we're sending
out-of-date diagnostics and then not updating the UI when things change.
That needs to be fixed.
