IM Overlap validation error

[bartneck]

When writing a simple IM Overlap repetition, a validation error occurs (see swiML/tests/IMO%20test/imo01.xml

    <!-- This should result in 25Fl/25BK and 25BR/25FR-->
    <instruction>
        <repetition>
            <repetitionCount>2</repetitionCount>
            <instruction>
                <length>
                    <lengthAsDistance>50</lengthAsDistance>
                </length>
                <stroke>
                    <standardStroke>individualMedleyOverlap</standardStroke>
                </stroke>
            </instruction>
        </repetition>
    </instruction>

[calloc262]

I had done this intentionally to minimize ambiguity as users can write 3x50 as fl/bk bk/br br/fr. If they could write 2x50 as fl/bk br/fr then at any multiple of 6x50 we dont know which to flatten to.
I can still allow the user to write multiples of 2x50 which will flatten to fl/bk br/fr but I will have to default to one or the other when its a multiple of both.