Incorrect values returned for `@RRS`

[NameOfTheDragon]

Testing of pull request #30 has revealed a puzzling issue as follows:

@FRS
FRS3.4.0-auto-close.5
@ZDS
ZDS
@RRS
RRS46000
@RWS,20000
RWS
@RRS
RRS200009

The final reading of @RRS returns the wrong value, always some extra data appended to the end.

Some thoughts on this:

• The XBee isn't implicated because it happens when issuing the commands locally on the shutter (as above).
• The command and payload appears to arrive intact when sent remotely from the rotator, as in this example: When sending @RWS,20000 from the rotator, the shutter emits Cmd @RWS,20000 which suggests that the data is arriving intact.
• Reading the configuration and performing microsteps-to-steps conversion doesn't appear to be implicated, because reverting to factory defaults restores the correct value, which it then reported correctly.
• The appended spurious data is always "09" so it doesn't seem to be a random memory corruption.

Conclusion: something is happening to the value between receiving it as a command and the value being written into the configuration structure.

This needs to be traced in detail to determine what's going wrong.

[NameOfTheDragon]

After reverting to factory defaults and resetting the target system, the problem can no longer be reproduced :(

[NameOfTheDragon]

Fixed by PR#30