Parameter Sets; update Number Range logic

When using a Number Range in a Parameter Set the logic of how From / To values were updated was confusing.

This has been updated so the value just entered will not change, i.e. the other value in the range will be updated if necessary.

For example, entering 10 in From, then 5 in To would switch the values so the range is 5 to 10. Now the From value will be updated to 5.