IcePAP axis state mix between greenlets/threads
The IcePAP controller class uses a member called
icestate to compose the state of an axis.
This member is used in
state() method to sequentially compose the state of a specific axis. At the end of the method,
self.icestate is returned.
This is a source of problems if
state() is called for two different axis in two different greenlets, for example.