mp49/parker6k — pull request #15 by mark0n (2014-11-18 20:16:38+00:00)
Title: improve S curve param check

Check if the S curve parameters that are sent to the controller are zero. The user might have set a value slightly above 0 but it might get truncated to 0 later. If that happens the following error occurs:
```
2014/11/18 13:24:25.571 p6kController::lowLevelWriteRead: ERROR: Command 1A0.00 returned an error: INVALID DATA-FIELD 1
```