Store the last used port and use it as default.

When opening a port for the first time the dropdown text will be blank (forcing you to use a port instead of accidentally selecting the first port in the list) but thereafter it will show the previously used port.

colourterm/connectdialog.py

@@ -209,6 +209,9 @@ class ConnectDialog(QtGui.QDialog, UiConnectDialog):
     def get_hardware_handshake(self):
         return self.hardware_checkbox.isChecked()
 
+    def set_port(self, port):
+        self.port_edit.setEditText(port)
+
     def update_port_combobox(self):
         self.port_edit.clear()
         ports = []

colourterm/mainwindow.py

@@ -201,11 +201,14 @@ class MainWindow(QtGui.QMainWindow, UiMainWindow):
 
     def on_open_action_triggered(self):
         self.connect_dialog.update_port_combobox()
+        settings = QtCore.QSettings()
+        self.connect_dialog.set_port(unicode(settings.value(u'previous-port', u'').toString()))
         if self.connect_dialog.exec_() == QtGui.QDialog.Accepted:
             if not self.device_closed:
                 self.device_closed = True
                 self.device.close()
             try:
+                settings.setValue(u'previous-port', self.connect_dialog.get_port())
                 self.device = Serial(
                     port=self.connect_dialog.get_port(),
                     baudrate=self.connect_dialog.get_baud(),