Fixed ids.

pyad2usb/ad2usb.py

@@ -202,6 +202,10 @@ class AD2USB(object):
         self._device.close()
         self._device = None
 
+    @property
+    def id(self):
+        return self._device.id
+
     def _wire_events(self):
         """
         Wires up the internal device events.

pyad2usb/devices.py

@@ -168,6 +168,10 @@ class USBDevice(Device):
 
         self.on_close()
 
+    @property
+    def id(self):
+        return self._id
+
     def is_reader_alive(self):
         """
         Indicates whether or not the reader thread is alive.
@@ -324,6 +328,10 @@ class SerialDevice(Device):
 
         self.on_close()
 
+    @property
+    def id(self):
+        return self._id
+
     def is_reader_alive(self):
         """
         Indicates whether or not the reader thread is alive.
@@ -458,6 +466,10 @@ class SocketDevice(Device):
 
         self.on_close()
 
+    @property
+    def id(self):
+        return self._id
+
     def is_reader_alive(self):
         """
         Indicates whether or not the reader thread is alive.