Fix for issue #381

Created by: mguijarr

• rate limitation decorator now drops events received in the delay interval
• motor states are handled individually (like motor positions since #373)
• as a consequence, signals.microdiffSignals and motor_signals have been purged from position and state signals
• CSS transition duration for motor states is 300 ms now instead of 1 s

We tested this on ID30A3 just now.