deviceMethodWidget.py: implement MethodEnabledByAttributeWidget
Fix issue 3 in the TapeDrive project.
A new method widget is created, where the input fields of the method can be enabled/disabled based on the value of a boolean attribute, belonging to the same device or not.
E.g. for the tapedrive start_run
method: the input field is disabled when the chopper is enabled (external trigger True).
Edited by Jerome Carnis