Allow a Bean to be returned by general queries (ie. RowsIterator(...))

[Nick-Lucas]

It makes sense that we don't allow a standard Bean to be returned as that would infer that use of Store() or Trash() are valid.

The RowToBean method is therefore useful here, but I'd like to profile the performance like for like.

If internal Bean creation is faster than we should create a QueryBean subclass or similar which Limebean knows not to try and store, and Kind == "" and can't be changed.