Cycleloop does not raise Exception, run_plc accept debug flag.

User has to use maxioerrors = n, if the program should crash on process
image errors.
If the ProcimgWriter helper is running but get no new data for 2500 ms,
the cycleloop will print just a warning. Cycle function is paused for
that time. Most interesting for RevPi NET classes.

setup.py

@@ -17,7 +17,7 @@ setup(
 
     license="LGPLv3",
     name="revpimodio2",
-    version="2.5.3a",
+    version="2.5.3b",
 
     packages=["revpimodio2"],
     python_requires="~=3.2",