* Process BlockHeadersMsg
* Print invalidations
* Print reason for parent-child mismatch
* Fix off by one error
* Fix ExtendDown
* Replace tipLimiter with an LRU cache
* Retrieve 256 headers at a time
* Hard coding of tips, process new block hashes
* extract headers
* Write hard-coded headers into a file
* Add total difficulty
* Insert hard coded headers
* Log i
* Initiate download from hard-coded anchors
* Print the state of anchors
* Add hard-coded headers as tips
* Spare the peers
* Refine LRU caching of tips
* Print length of anchor trees
* Limit requests to 192 headers
* range error fix
* Print better, retain at least one tip in the LRU cache
* Skip duplicate line ends
* Throttle requests, display peer name
* Back off, intermediate tip queue
* Print block header timestamp
* Better logging
* Log less
* More logging of evictions
* Fix queue push
* Fix queue pop
* Exclude duplicate tips
* Fix tips logging
* Fix moving
* Add port flag
* Check headers
* Print extra
* Add mixDigest to serialisation
* Fix difficulty in hard-coded headers
* Avoid duplicate header requests
* Update peer characteristics on NewBlockMsg
* Remove backoff when peer responds
* Fix tests
* Fix lint
* Fix lint