Provide the ability to expire or make a sales tax code inactive (cannot be used).

 A while back, we set up duplicate tax codes for some states for the purpose of having freight being non-taxable under certain conditions.  We have since gone away from this method and went back to using a single tax code per taxing entity.  Unfortunately, people are still using the tax codes where freight is non-taxable and there seems to be no way to prevent this.  We need to keep these non-taxable freight tax codes for historical purposes and for any credit/rebills.  The only way it seems that we can stop this - is to physically delete the un-wanted tax codes.