* implement get_churn_limit from 0.6.1; update initiate_validator_exit and get_previous_epoch to 0.6.1; remove obsoleted/non-spec reduce_balance, replaced by decrease_balance; mark BeaconBlock as 0.6.1
* rename get_block_root to get_block_root_at_slot and introduce epoch-oriented get_block_root; implement get_attestation_slot, get_matching_source_attestations, get_matching_target_attestations, get_matching_head_attestations, 0.6.1 get_attesting_indices, get_unslashed_attesting_indices, get_attestation_deltas, process_rewards_and_penalties; rm get_inactivity_penalty
* update Validator and processVoluntaryExits to 0.6.1; rm obsolete inclusion_slots/inclusion_distances
* rm removed activate_validator; mark DepositData, misc values, Gwei values, Randao processing, state caching as 0.6.1; update GENESIS_SLOT to 64, since it doesn't quite yet work at 0
* mark BeaconBlockHeader as 0.6.1; update BeaconBlockBody to 0.6.1; rename WHISTLEBLOWER_REWARD_QUOTIENT to WHISTLEBLOWING_REWARD_QUOTIENT; update slash_validator to 0.6.1
* implement 0.6.2 is_slashable_validator; update processProposerSlashings to 0.6.2; mark state caching as 0.6.2
* mark get_total_active_balance and process_slashings as 0.6.2; update get_base_reward to 0.6.2
* rm prepare_validator_for_withdrawal, process_exit_queue; mark mainnet misc constants as 0.6.2; update process block header to 0.6.2
* address mratsim's code review comment
* Initial move constants to mainnet preset
* Bump fixtures to include shuffling with minimal preset
* Add minimal preset with shuffling test
* Add minimal preset to the full test suite
* use preset() everywhere
Dustin Brody
Mamy Ratsimbazafy