* Renamed fork_choice::process_attestation_from_block
* Processing attestation in fork choice
* Retrieving state from store and checking signature
* Looser check on beacon state validity.
* Cleaned up get_attestation_state
* Expanded fork choice api to provide latest validator message.
* Checking if the an attestation contains a latest message
* Correct process_attestation error handling.
* Copy paste error in comment fixed.
* Tidy ancestor iterators
* Getting attestation slot via helper method
* Refactored attestation creation in test utils
* Revert "Refactored attestation creation in test utils"
This reverts commit 4d277fe4239a7194758b18fb5c00dfe0b8231306.
* Integration tests for free attestation processing
* Implicit conflicts resolved.
* formatting
* Do first pass on Grants code
* Add another attestation processing test
* Tidy attestation processing
* Remove old code fragment
* Add non-compiling half finished changes
* Simplify, fix bugs, add tests for chain iters
* Remove attestation processing from op pool
* Fix bug with fork choice, tidy
* Fix overly restrictive check in fork choice.
* Ensure committee cache is build during attn proc
* Ignore unknown blocks at fork choice
* Various minor fixes
* Make fork choice write lock in to read lock
* Remove unused method
* Tidy comments
* Fix attestation prod. target roots change
* Fix compile error in store iters
* Reject any attestation prior to finalization
* Fix minor PR comments
* Remove duplicated attestation finalization check
* Remove awkward `let` statement
