CVC3 doesn't allow decimal points, thus always use fractions.

CVC3 doesn't allow decimal points to represent rational numbers.  Thus simplify
things by putting the literal into fractional form.  Currently reduction is
not attempted, and the simplest form is used.  Ex. 4.56 becomes (456/100) (as
tested in the accompanying unit test).

git-svn-id: https://groke.mcmaster.ca/svn/grad/colin/branches/TableTool_javization@10714 57e6efec-57d4-0310-aeb1-a6c144bb1a8b