Spec v0.9.0 updates - eth2 part

[hwwhww]

What is wrong?

https://github.com/ethereum/eth2.0-specs/releases/tag/v0.9.0

• features
  • alter beacon proposer selection logic (Improve beacon proposer selection logic consensus-specs#1413)
  • add seed domains (Add seed domains consensus-specs#1415)
  • fix delay-based attestation inclusion reward (Fix delay-based attestation inclusion reward consensus-specs#1434)
  • use eth1_block_hash for initial randao_mix (Implement solution for #1446, based on suggested use of eth1 hash consensus-specs#1447)
• simplifications
  • remove active active_index_roots and compact_committees_roots from phase 0 (Remove light client infrastructure from phase 0 consensus-specs#1329)
  • remove shards/crosslinks from phase 0 (Remove Shards/Crosslinks from Phase 0 consensus-specs#1428)
  • remove transfers from phase 0 (Remove transfers from phase 0 consensus-specs#1443)
• Fork choice
  • verify state root in fork choice tests and other minor fixes (Forkchoice tests fixed consensus-specs#1454)

How can it be fixed

Question: should the v0.9 progress on the new branch, so that interop tests can still work?
@ralexstokes

[ralexstokes]

@hwwhww awesome! sounds like you want to do some further refactoring in #1251 so reviewing this will be top of my list after you get that done :)

in the meantime, i'd suggest we just move ahead w/ merging this to master we can always rewind to a particular point if we need to but i'd rather have an incentive for another team to update so we can do v0.9.0 interop experiments