Change BinaryFormat to XMLFormat, watch test break.

testSerialization.swift

    func testWeirdSerialiation() {
        let exp = NSDate()
        do {
            let data = try NSPropertyListSerialization.dataWithPropertyList(exp, format: .BinaryFormat_v1_0, options: 0)
            do {
                var format: NSPropertyListFormat = .BinaryFormat_v1_0
                if let got = try NSPropertyListSerialization.propertyListWithData(data, options: .MutableContainersAndLeaves, format: &format) as? NSDate {
                    let foo = got.timeIntervalSinceDate(exp)
                    XCTAssertEqual(got, exp, "Dates were not the same: \(foo).")
                } else {
                    XCTFail("Deserialized date is nil.")
                }
            } catch let error as NSError {
                XCTFail("Couldn't deserialze data: \(error).")
            }
        } catch let error as NSError {
            XCTFail("Couldn't serialize data: \(error).")
        }
    }