* relax attestation validation when attestation is incoming but make it
more strict when adding to block
* share attestation validation logic between attestation pool and state
transition
* remove a bunch of redundant logging
* fix potential underflow in attestation delay checking
* fix committee used for attestation shard selection when attesting
* fix attestation data construction
* State sim compiles and run
* Works on libp2p testnet1
* Successfully update the state transition tests
* naive update of attestation pool (failing attstations can arrive in any order)
* Remove an official assert to allow attestation reordering
* rename get_genesis_beacon_state(...) to initialize_beacon_state_from_eth1(...); remove unused vestiges get_temporary_block_header(...) and get_empty_block(...); partly align initialize_beacon_state_from_eth1(...) with 0.8.0 version; implement CompactCommittee object type; update process_final_updates(...) to 0.8.0
* mark get_shard_delta(...) as 0.8.0
* mark get_total_active_balance(...) and epoch transition helper functions as 0.8.0
* move FORK_CHOICE_BALANCE_INCREMENT, not in spec anymore, to sole user in fork_choice
* rename slot_to_epoch(...) to compute_epoch_of_slot(...)
* rename aggregation_bitfield/custody_bitfield fields to aggregation_bits/custody_bits; rename convert_to_indexed(...) to get_indexed_attestation(...); mark BeaconBlockHeader as 0.8.0; update minimal preset MIN_ATTESTATION_INCLUSION_DELAY/time parameters in general to 0.8
* fix beacon node compilation; it used slightly different capitalizations of slot_to_epoch/slotToEpoch
* mark integer_squareroot(...), Deposit, VoluntaryExit, and Transfer as 0.8.0; rename get_epoch_start_slot(...) to compute_start_slot_of_epoch(...)
* add new Domain alias for uint64; rename bls_domain(...) to compute_domain(...), MAX_INDICES_PER_ATTESTATION to MAX_VALIDATORS_PER_COMMITTEE, and SignatureDomain to DomainType; update get_domain(...) to 0.8.0
* update/mark initiate_validator_exit(...) and Crosslink as 0.8.0; rename BeaconState.latest_block_roots -> BeaconState.block_roots; mark HistoricalBatch as 0.8.0
* migrate attestation pool tests from get_crosslink_committees_at_slot(...) to get_crosslink_committee(...)
* rm obsolete, unused get_crosslink_committees_at_slot_cached(...) and migrate tests/test_state_transition from get_crosslink_committees_at_slot(...) to get_crosslink_committee(...)
* migrate tests/testutil from get_crosslink_committees_at_slot(...) to get_crosslink_committee(...)
* use more pervasive caching infrastructure, initially of compute_committee; remove buggy (and per-index) shuffling to fix research/state_sim, which was noticing validators on multiple shard committees; rm now-unused specific get_attesting_balance_cached
* add some get_active_validator_index caching
* rm obsolete/unused get_attesting_indices_cached
* rm get_crosslink_committees_at_slot(...)
* some more 0.7 changes -- some of which can't be completed pending some data structure updates -- and shard handling changes to offset with epoch start shards
* Initial move constants to mainnet preset
* Bump fixtures to include shuffling with minimal preset
* Add minimal preset with shuffling test
* Add minimal preset to the full test suite
* use preset() everywhere
* 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
* keep track of a finalized block
* keep track of all justified blocks
* use naive spec version of LMD ghost
* cache slot number and a few more things in BlockRef
* keep track of the latest vote of each validator
* depend less on the state of node.state (it's a cache, effectively)
* fix state db lookup typo
* fix randao reveal slot when proposing blocks
* only store blocks that can be applied to a state
* store state at every epoch boundary (yes, needs pruning!)
* split out state advancement function when there's no block
* default state sim to 0.9 attestation ratio
* implement in-memory block graph
* store tail block in database
* resolve unknown parents by syncing them from peers
* introduce concept of resolved blocks and attestations - those that
follow minimal protocol rules
* update state head lazily
* log more stuff
* shortHash -> shortLog
* start 9/10 beacon nodes by default, last can be started manually
* see also #134
* fix start.sh epoch length
* convert some asserts to doAsserts to keep them in release mode builds; rename get_initial_beacon_state to get_genesis_beacon_state to track spec; switch target spec version to 0.3.0; switch references to penalize_validator to slash_validator/slashValidator to track spec; make some function returns safer by omitting 'return'
* 2x shuffling speedup by hoisting pivot calculations per https://github.com/protolambda/eth2-shuffle
* fix initial attestation pool on reordered attestations
* simplify db layer api
* load head block from database on startup, then load state
* significantly changes database format
* move subscriptions to separate proc's
* implement block replay from historical state
* avoid rescheduling epoch actions on block receipt (why?)
* make sure genesis block is created and used
* relax initial state sim parameters a bit
* move attestation pool to separate file
* combine attestations lazily when needed
* advance state when there's a gap while attesting
* compile beacon node with optimizations - it's tooo slow right now
* log when unable to keep up