Until now, when using, for example, VAT, you put like this:

price=0.196, efficiency=1.0

so the result by getAggregatedAmountList is, if the base is 100:

price=0.196, efficiency=1.0, quantity=100

Thus, the total price is 19.6.

This works but not compatible with rounding, as, for instance, if we want to 
round it up to 20, the result is not saved at anywhere.

So, from now on, we do like this instead:

price=1.0, efficiency=0.196

so the result is:

price=1.0, efficiency=0.196, quantity=100, total price=19.6

The total price does not change. When we apply a rounding method, it would 
result in:

price=1.0, efficiency=0.196, quantity=100, total price=20

--

This modification is approved by YO and Yusei.

TODO: write some test-cases



git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@30019 20353a03-c40f-0410-a6d1-a30d3c3de9de