Move duplicate identical item array declarations into new abc::_raw_vextr_item_array
Add support for retrieving abc::_raw_vextr_item_array from its first item
Rename _raw_vextr_impl_base::transaction to _raw_vextr_transaction, make it use _raw_vextr_impl_base as storage
Fix code documentation
Use _raw_vextr_item_array to hold dynamically-allocated item arrays
Change abc::_raw_vextr_packed_data to store “real item array” flag instead of capacity