api stays the same, specification changes slightly

the following expression, which would throw an exception in the previous version, is now valid. It returns "2":
	toInt (undefined :: N2)
renamed one function
added a way to represent rational numbers at compile time
SGCard exports SGCard.Ratio now
export "FractionClass" and its functions as well
depends on newer versions of some popular libraries now.

This forces a major version change
fixed .cabal to point to the right version
Merge tag '1.3.0.0' into testing
added an example
Merge branch 'testing' into release