* allow running more or fewer validators
* use deterministic key generation for tests to avoid exhausting system
RNG
* update README with simulator docs
* write the data of each validator to separate file, instead of a big
chainstart.json (makes it easier to run different validator counts)
* 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
* s/slot_included/inclusion_slot/; s/participation_bitfield/aggregation_bitfield/; rearrange some type definitions to match spec order
* a couple more Eth1Data-related spec syncs
You'll need the latest versions of nim-eth-p2p, nim-serialization
and nim-json-serialization.
Before starting the simulation script, make sure to delete any previous
json files from the simulation folder:
```
rm tests/simulation/*.json
tests/simulation/start.sh
```
This should survive the creation of few blocks before diying with a
block validation error.
* spec updates
* balances move out to separate seq
* bunch of placeholders for proof-of-custody / phase1
* fix inclusion distance adjustment
* modify state in-place in `updateState` (tests spent over 80% time
copying state! now it's down to 25-50)
* document several conditions and conversations
* some renames here and there to follow spec
* spec updates
* random small updates
* ssz no longer sorts by field, fix enum serialization
* rewire block processing a little to avoid a few state copies
* add a state simulation tool that writes out jsons
* ssz: finish implementation
* add object support, simplify implementation
* fix extra round of hashing in tree_hash_root
* ssz: cleanups
* work around Nim range bug for Uint24, cleanups