- do not break from headsection on error
[remove peer after protocol quit will close switchC, until then head block can arrive and block on channel while keeping peers lock causing a deadlock.]
- more careful locking in AddBlock
- blockpool moves to its own package
- uses errs pkg for its own coded errors
- publicly settable config of params (time intervals and batchsizes)
- test helpers in subpackage
- optional TD in blocks used now to update peers chain info
- major improvement in algorithm
- fix fragility and sync/parallelisation bugs
- implement status for reporting on sync status (peers/hashes/blocks etc)
- several tests added and further corner cases covered