9af9ca9518
* split horizon into two explicit values for cut through and txhashset request * let node which has 2-7 days of history be able to handle forks larger than 2 days * add test simulate_long_fork * add pause/resume feature on p2p for tests * refactor the state_sync * ignore the test case simulate_long_fork for normal Travis-CI * refactor function check_txhashset_needed to be shared with body_sync * fix: state TxHashsetDone should allow header sync