* Most of the PR changed files are extra and slightly more complicated
unit tests.
* Fixed Eth1DataVotes not inheriting genesis
* Fixed Attestations simulation using wrong slot when reconstructing
partecipation
* Fixed Copy() operation on BeaconState on Eth1DataVotes
* Used correct ListSSZ type for Eth1DataVotes and HistoricalSummaries
* Fixed wrong []uint64 deltas on empty slots
we need to extract this interface from the struct.
i need to also break down the interface more, to better show what parts
the caching is used, move some functions from the cache state to the
underlying.
don't merge
