reworked attocube

- step_mode: soft closed loop, stepwise, reading encoder after a delay
- calib_steps command to determine step size

Change-Id: I27bdffb4d564ac9c55a6473704ac2de6ad92bac8

cfg/attocube_cfg.py

@@ -10,7 +10,9 @@ Mod('r',
     value = Param(unit='deg'),
     tolerance = 0.01,
     target_min = 0,
-    target_max = 360
+    target_max = 360,
+    steps_fwd = 50,
+    steps_bwd = 100,
     # gear = 1.2,
 )