Save & Continue Editing defaults to false for reference

[Randle Taylor]

When setting references and tolerances for a boolean test and you sit "save and continue editing" the reference value defaults to No rather than whatever it was before.

[Randle Taylor]

I've changed this so that when you load the "Set References & Tolerances" page for a boolean test, a blank value is used rather than Yes or No. That way a user is much less likely to change a reference value by accident since a blank value will give a validation error.