[GNC] Invoice tax rouding issue in 2.x

[Matthew Pounsett]

Thanks for all your replies.  If just the people who have replied in the
last 12 hours is any indication, then a lot of people are "living with" a
fairly annoying bug.

In my case, this is on an invoice I'm generating, not a bill, so I don't
feel like I can mess with the data too much.  Fortunately (or not) I'm not
using GnuCash to actually generate the invoice that goes to the customer,
since I find them poorly implemented as well... so the invoice is just for
internal records.  But that means it needs to match what I actually send
the customer fairly accurately, or things get "off".

My workaround is to add -$0.01 item that is non-taxable but is posted to my
tax table's liability account.