* update most of the remaining non-fork-choice spec refs, updating code where necessary
* revert presumably harmless compute_signing_root() change, but this way, keep things really unchanged outside inspector
* sync fixes
* fix Status message finalized info
* work around sync starting before initial status exchange
* don't fail block on deposit signature check failure (fixes#989)
* print ForkDigest and Version nicely
* dump incoming blocks
* fix crash when libp2p peer connection is closed
* update chunk size to 16 to work around missing blocks when syncing
* bump libp2p
* bump libp2p
* better deposit skip message
* add another check for inconsistent aggregation and committee length, since ncli_transition bypasses process_attestation(...)/check_attestation(...) and calls almost directly into process_epoch(...)
* bump validator functions to v0.11.1 spec references
* bump some spec references to v0.11.1
* poke
* initial attestation aggregation
* fix usage of committee index, vs index in committee; uniformly set trailing/following distance; document how the only-broadcast-if mechanism works better and what aggregation already happens, not otherwise sufficiently clear; use correct BlockSlot across epoch boundaries
* address inconsistent notion of which slot in past to target for aggregate broadcast; follow 0.11.x aggregate broadcast p2p interface topic
* Fix get_slot_signature(...) call after get_domain(...) change required genesis_validators_root
* mark all spec references which aren't dealt with in other PRs as v0.11.1
* update two more spec refs to v0.11.1
* complete (except for get_domain(...)) 0.11.0 beacon chain spec update
* mark compute_start_slot_at_epoch(...), is_active_validator(...), compute_signing_root(...), and get_seed(...) as 0.11.0