day count basis tests

For some reason I do not seem to be able to post this to the doc library, 
so sending via email.

This is update of the day count basis test cases.  I've enumerate all of 
the 32 permutations of the 5 conditions for Actual/Actual. And did manual 
calculations on each one.  I found one discrepancy, which I traced to an 
error in the function write up, an error I introduced.  So that is fixed.

-Rob