Add some basic parsing tests for length|percentage filter functions. We don't reject negative values right now, so some of these tests fail.
Add comparsion operators to nsCSSValue for < 0, > 100% comparsions.
Add >= 0% and <= 100% constraints for the appropriate filter function arguments. Also, remove drop-shadow and hue-rotate parsing for now. These won't make it in the first patch.
Fall through to false bug fix in nsCSSParser. Was causing the new tests to fail.