Polling of analogue or digital pins now causes an exception

Some users just don't read the README, do some polling instead
of using callbacks and then fire off an issue
(#16).

To prevent wasting my time the library now does a hard
exception if somebody tries polling. This then recommends
pyfirmata1.

examples/scan.py

@@ -1,7 +1,9 @@
-import serial
-import serial.tools.list_ports
-
-print("Serial devices available:")
-l = serial.tools.list_ports.comports()
-for ll in l:
-    print(ll.device, ll.description)
+#!/usr/bin/python
+
+import serial
+import serial.tools.list_ports
+
+print("Serial devices available:")
+l = serial.tools.list_ports.comports()
+for ll in l:
+    print(ll.device, ll.description)

pyfirmata2/pyfirmata2.py

@@ -588,7 +588,7 @@ def read(self):
         if self.mode == UNAVAILABLE:
             raise IOError("Cannot read pin {0}".format(self.__str__()))
         if (self.mode is INPUT) or (self.mode is INPUT_PULLUP) or (self.type == ANALOG):
-            warnings.warn("Use a callback handler for pin {0}".format(self.__str__()))
+            raise IOError("Reading via polling is not supported by this library. Please use the original pyfirmata.")
         return self.value
 
     def register_callback(self, _callback):

setup.py

@@ -7,7 +7,7 @@
 
 setup(
     name='pyFirmata2',
-    version='2.4.6',
+    version='2.5.0',
     description="Use your Arduino as a data acquisition card under Python",
     long_description=long_description,
     author='Bernd Porr',