`stdEnumerator` - Better `CreateFromIEnumVariant()`

[sancarn]

Currently CreateFromIEnumVariant() enumerates the entire collection and converts it into an array at Create-Time. This is awful.

In reality we should call the IEnumVARIANT's Next method to obtain the next element in the collection as and when it is needed. This would allow things such as first(100) to be used effectively without lagging out.

Unfortunately this requires behaviour only made available recently in stdCOM so expect we'll have to port those over as required.