* have regular slot tick, decide on work to do lazily
* use beacon clock instance that will eventually sync time
* skip work when falling behind
* add one more state cache for justified state (since that's used in
fork choice)
* remove old sync cruft
* single timer per slot, serializing block production and attestation
With these changes, running a simulation is very close to running
an actual testnet. Some checks have been added in the client to
make sure you are not connecting to an incompatible network (e.g.
a network running with a different number of shards).
* 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)
* 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
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.
Jacek Sieka
Zahary Karadjov
Ștefan Talpalaru
Jacek Sieka
Dustin Brody
Mamy Ratsimbazafy
Yuriy Glukhov