Also start reworking the USBPrint.

It's also time for some much needed code cleaning in that bit. The auto-detect is moved to it's own job,
which should make it a whole lot easier to disable it all together.

CL-541

plugins/USBPrinting/AutoDetectBaudJob.py

@@ -0,0 +1,44 @@
+# Copyright (c) 2017 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from UM.Job import Job
+from UM.Logger import Logger
+
+from time import time
+from serial import Serial, SerialException
+
+class AutoDetectBaudJob(Job):
+    def __init__(self, serial_port):
+        super().__init__()
+        self._serial_port = serial_port
+        self._all_baud_rates = [115200, 250000, 230400, 57600, 38400, 19200, 9600]
+
+    def run(self):
+        Logger.log("d", "Auto detect baud rate started.")
+        timeout = 3
+
+        for baud_rate in self._all_baud_rates:
+            Logger.log("d", "Checking {serial} if baud rate {baud_rate} works".format(serial= self._serial_port, baud_rate = baud_rate))
+            try:
+                serial = Serial(str(self._serial_port), baud_rate, timeout = timeout, writeTimeout = timeout)
+            except SerialException as e:
+                Logger.logException("w", "Unable to create serial")
+                continue
+
+            successful_responses = 0
+
+            serial.write(b"\n")  # Ensure we clear out previous responses
+            serial.write(b"M105\n")
+
+            timeout_time = time() + timeout
+
+            while timeout_time > time():
+                line = serial.readline()
+                if b"ok T:" in line:
+                    successful_responses += 1
+                    if successful_responses >= 3:
+                        self.setResult(baud_rate)
+                        return
+
+                serial.write(b"M105\n")
+        self.setResult(None)  # Unable to detect the correct baudrate.