Support iPod touch on iOS 7

- iPod touch on iOS7 doesn't have `iPod;`, it has `iPod touch;`
- Test case is from https://github.com/woothee/woothee/pull/6

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I don't know how to update submodule woothee because https://github.com/woothee/woothee/pull/6 is not merged yet.
I think other implementations should support this test case.