In Python 3.0, the Decimal __round__, __ceil__ and __floor__ functions
don't work as intended:  they all return 1, 0, or -1.

This is easy to fix.  The only reason I'm making an issue (literally) of 
it is that I remember some discussion of whether these functions should
be implemented at all for Decimal, but I don't remember what the outcome 
of that discussion was.  Adding Jeffrey to the nosy list in case he 
remembers.

Either all three functions should be removed, or they should be 
corrected and tests should be added for them.