A filter to add or subtract a value from a given date using the methods Add and Subtract

[nicholasruggeri]

Pull request for issue #170.

[urish]

Looks good, thanks!

Can you please:

1. Rename them to amAdd, amSubtract to keep it consistent with the other filters
2. Add tests for them

Thanks!

[nicholasruggeri]

Thank you @urish ;)
All done.

[urish]

Thanks!

[urish]

p.s. I have improved the tests, they now explicitly state the expected result as you originally intended to do:

    it('should subtract 1 hour from date', function () {
        var date = new Date(2000, 1, 1, 0, 0, 0);
        expect(amSubtract(date, 1, 'hours').toString()).toMatch(/^Mon Jan 31 2000 23:00:00/);
    });

[urish]

Released as 0.10.3