Allows compatibility with older wavefront (.wft) files

[gr5]

Sorin noticed this "bug" introduced in v7.3.1. This only affects people who create wft files with other software. Software other than DFTFringe.

[github-actions]

🚀 New build available for commit 2b56e4a
Download installer here

[gr5]

So then Dale, should I change this one to save the string "nulled" instead? And note that the code that reads this line ignores the "1" so if someone puts a "0" instead of a "1" it won't change how the file is interpreted.

DFTFringe/surfacemanager.cpp

Lines 993 to 994 in 55d8092

	if (!wf->useSANull){
	file << "Do Not use null" << 1 << std::endl;

[gr5]

Or can we leave it as is in this PR.

[githubdoe]

I think it should be put to what it use to be. I'm not really sure if i changed it now. But if I did it was for debugging purposes and forgot to put it back.