Spec sync

[ralexstokes]

What was wrong?

I was looking at exactly what functionality remained to reach our first pass at a full state transition function for the beacon chain.

How was it fixed?

The existing code was compared to the current spec. There was some refactoring done to make parts of the state transition more manageable.

Cute Animal Picture

[ralexstokes]

need to fix linter

[ralexstokes]

@hwwhww heads up if this is merged, there may be a merge conflict w/ #314.

[ralexstokes]

pending spec changes, here is the missing functionality required to complete the beacon chain state transition function:

• process_randao -- ralexstokes will enable, addressing issue Enable process_randao #284
• process_attester_slashings -- PR Implement process_attester_slashings #299
• process_deposits -- issue Implement the rest of block operations #238 (open, check w/ hwwhww)
• process_voluntary_exits -- issue Implement the rest of block operations #238 (open, check w/ hwwhww)
• process_transfers -- issue Implement transfer operation processing #325 (open)
• process_eth1_data_votes -- issue Implement eth1_data_vote processing per block #326 (open)
• process_ejections -- issue Implement process_ejections #287 (open)
• process_slashings -- issue Implement beacon chain state transition process_slashings #322 (open)
• process_exit_queue -- issue Implement beacon chain state transition process_exit_queue #323 (open)

edit: add cute lil checkboxes to indicate they are in flight to being merged

[hwwhww]

The logic looks good to me 👍
Another nitpick: rename local variable num_shards_in_committees to current_epoch_committee_count to match the spec.

Defer to @pipermerriam on the inner function usage.