A subtle interaction between incr/decr on the items in the metrics view
and the kerning word list entry where it used to add/subtract from the kerning
word if that word happened to be an integer.

Note that you can't move the below if() block up or unexpected things happen too.
So the best seems to be to selectively avoid the add/subtract just on the kerning
word list entry box.
Merge pull request #451 from monkeyiq/2013mar/issues/447

A subtle interaction between incr/decr on the items in the metrics view