* Decouple Segments from Turns in Storage
* Get replicator local cluster tests running in a reasonable amount of time
* Fix unused imports
* Document new RPC APIs
* Check for exit while polling
* change consecutive leader slots to 4
* reduce polling frequency for transaction signature confirmation
* adjust wait time for transaction signature confirmation
* fix nominal test
* fix flakiness in wallet pay test
* Implement CreditOnlyLocks
* Update credit-only atomic on account load
* Update credit-only atomic after bank.freeze_lock; store credits if all credit-only lock references are dropped
* Commit credit-only credits on bank freeze
* Update core to CreditAccountLocks
* Impl credit-only in System Transfer
* Rework CreditAccountLocks, test, and fix bugs
* Review comments: Pass CreditAccountLocks by reference; Tighten up insert block
* Only store credits on completed slot
* Check balance in bench_exchange funding to ensure commit_credits has completed
* Add is_debitable info to KeyedAccount meta to pass into programs
* Reinstate CreditOnlyLocks check on lock_account
* Rework CreditAccountLocks to remove strong_count usage
* Add multi-threaded credit-only locks test
* Improve RwLocks usage
* Review comments: panic if bad things happen; tighter code
* Assert lock_accounts race does not happen
* Revert panic if bad things happen; not a bad thing
* Add storage point tracking and tie in storage rewards to epochs and economics
* Prevent validators from updating their validations for a segment
* Fix test
* Retain syscall scoping for readability
* Update Credits to own epoch tracking
* Add signature to blob
* Change Signable trait to support returning references to signable data
* Add signing to broadcast
* Verify signatures in window_service
* Add testing for signatures to erasure
* Add RPC for getting current slot, consume RPC call in test_repairman_catchup for more deterministic results
* Add credit-only debit/data check to verify_instruction
* Store credits and pass to accounts_db
* Add InstructionErrors and tests
* Relax account locks for credit-only accounts
* Collect credit-only account credits before passing to accounts_db to store properly
* Convert System Transfer accounts to credit-only, and fixup test
* Functionalize collect_accounts to unit test
* Review comments
* Rebase
* Add credit-only flag to AccountMeta, default to false
* Sort keys by is_credit_only within signed/unsigned groupings
* Process and de-dupe program keys along with other account keys
* Add message helper functions
* Fix test
* Improve comment
* s/is_credit_only/is_debitable
* Add InstructionKeys helper struct, and simplify program_position method
* Add num_readonly_accounts slice
* Impl programs in account_keys
* Emulate current account-loading functionality using program-account_keys (breaks exchange_program_api tests)
* Fix test
* Add temporary exchange faucet id
* Update chacha golden
* Split num_credit_only_accounts into separate fields
* Improve readability
* Move message field constants into Message
* Add MessageHeader struct and fixup comments
