* fix node.state being used unsafely across async callbacks (fixes#230)
* node.state -> node.stateCache
* fix attestation validation not to use asserts
* re-enable attestation pool tests
* prepare for resizing validator registry
* rm now-superceded shuffling cache (shuffling is only called from get_crosslinks), which was badly architected due to trying to exist in state; rm one more vestige of previous light-client regime (one more to go, from datatypes)
* fix wrong shuffling list size (active validator size, not validator size) to make consistent with 0.5.1 (will be inconsistent with testnet0); fix typo and change defaults in state_sim
* doAssert a couple of constant relationships necessary to avoid underflow; rm non-spec, unused helper function get_new_recent_block_roots
* refactor separate crosslink_committee_cache and winning_root_participants_cache(s) into StateData object; remove last vestige of previous shuffling cache
* separate out caching parts of StateData to new StateCache object
* ssz: avoid memory allocations
* a bit fishy with the 32-item stack.. this should be a smallvector
* digest: avoid another burnmem
* avoid a few allocations by using iterator
* avoid crash on invalid block production (fixes#209)
* fetch blocks every second, roughly
* fix start.sh param order
* run beacon node sim at slower pace
this is the beginning of tracking block-slots more precisely, so we can
the justification epoch slot bug.
* avoid asyncDiscard (swallows assertions)
* fix attestation delay
* fix several state root cache bugs
* introduce workaround for genesis epoch spec issue
* On the testnet site, the first N instead of the last N validators
will be considered reserved for users
* The number of validators is consistently named `totalValidators`
in all commands
* Proper keys are generated by default in validator_keygen
* no need to pass prev_block_root when updating state
* some Slot fixes
* fix `hash_tree_root` for Slot, Epoch
* detect missing hash_tree_root type support
* remove some <0.5 state checks