improve picontrol

after suggestions from Marek (WIP)

- keep Mareks version created during Markus absence for now
- add a class with input_module (which is not a mixin)
- not 100 % tested: HasConvergence now inherits from Drivable

Change-Id: I6b3896e7c0fdaa4379d1cbc5603d43bd7a0b3a48

frappy_psi/convergence.py

@@ -19,12 +19,12 @@
 #
 # *****************************************************************************
 
-from frappy.core import Parameter, FloatRange, BUSY, IDLE, WARN
+from frappy.core import Drivable, Parameter, FloatRange, BUSY, IDLE, WARN
 from frappy.lib.statemachine import StateMachine, Retry, Stop
 from frappy.lib import merge_status
 
 
-class HasConvergence:
+class HasConvergence(Drivable):
     """mixin for convergence checks
 
     Implementation based on tolerance, settling time and timeout.