Fix double-checking bug and simplify job queueing - aec_sync should simply assume that a received_block shall be forwarded - remove the caching of blocks, and the subsequent synchronization   mess. Simply include the block in each queued job. - Remove the RECV_POOL ets table, since it's no longer needed.
Fix double-checking bug and simplify job queueing
- aec_sync should simply assume that a received_block shall be forwarded
- remove the caching of blocks, and the subsequent synchronization
  mess. Simply include the block in each queued job.
- Remove the RECV_POOL ets table, since it's no longer needed.

aeternity/epoch,aeternity/epoch,aeternity/epoch,aeternity/epoch