Fix lessThan validation.
Fix lessThan validation.

lessThan should check whether its value is less than the value
of another field, in monetary regard.

This is

 23 <  42  -> true
-23 < -42  -> true  (and that was the bug)

stesie/geierlein,vog/geierlein,stesie/geierlein,stesie/geierlein,vog/geierlein,vog/geierlein,stesie/geierlein,stesie/geierlein,vog/geierlein,vog/geierlein