Improve logging of design decisions in `designLog.txt`

[smiths]

In the designLog.txt file, which shows the values of the design variabilities for a given generated example, the text when there is no logging code generated is incomplete. When there is no logging, the following is output in the designLog.txt file:

Logging selected as.

As an example, this is the output in the designLog.txt file for projectile_u_p_nol_u_wi_v_d.

I suggest that we change the output in this case to:

Logging selected as None.

[balacij]

The actual designLog.txt file is also ignored by the diff checks against stable/. It might be good to add it back so that people remember to also update the designLog.txt files when they update stable/ (I think they're out of date right now for some of the examples).

[JacquesCarette]

I'll bump that up to "would be a really goo idea" to add it back. [Why was it removed?]

[balacij]

I'm not too sure why it was removed (it might have been an accident? I remember changing designLog.txt files previously), but I can probably handle this ticket (and the bit about adding the .txt file inclusion to the diffs). However, as always, if anyone wants to knock it out before me, please feel free to.

[smiths]

@balacij there isn't any immediate urgency, but this would be a nice issue to close since we may use the design log in examples that we put in future papers.