Close engines in a proper way

[tico-tico]

Some engines like ProDeo really prefer to be closed in a proper way sending quit instead of just killing the process.
Here's a proposed change for EngineThread.py.

[...]
import sys
[...]

    def close(self):
        self.working = False
        if self.pid:
            self.put_line("quit")     # try to close the engine properly

            wtime = 40                # wait for it, wait for it...
            while self.process.poll() is None and wtime > 0:
                time.sleep(0.05)
                wtime -= 1

            if self.process.poll() is None:  # nope, no luck
                sys.stderr.write("INFO: the engine %s won't close properly.\n" % self.exe)
                self.process.kill()
                self.process.terminate()

            self.pid = None

No sure if I've broken anything, my python is retarded. 😱

[lukasmonk]

I like the solution.
It is included in my copy.
Thank you very much.