pyramid is using lengthUnitType

[bartneck]

The pyramid element is still using the <lengthUnitType> type, which has the option for meters, yards, lapse and time. The newer <length> element is using lengthAsDistance, lengthAsTime and lengthAsLaps. The pyramid needs to be updated to the new style.

[calloc262]

I've updated the XSD so that the pyramids use lengthType instead of lengthUnitType,
I also added an assertion to make sure that both startLength and stopLength are of the same type.

[bartneck]

The <incremenentLengthUnit> of the pyramid still uses lengthUnitType. It is also still included as a xs:simpleType. This needs to be removed completely to avoid confusion.