I think that for str(), the current method is better - using the new
repr() method will make str(1.1*3) == '3.3000000000000003', instead of
'3.3'. (The repr is right - you can check, and 1.1*3 != 3.3. But for
str() purposes it's fine.)

But I actually think that we should also use Tcl's decimal to binary
conversion - otherwise, a .pyc file created by python compiled with
Microsoft will cause a different behaviour from a .pyc file created by
python compiled with Gnu, which is quite strange.