add parallel fast sync support (#238)

add parallel fast sync support (#238)

* Add parallel require blocks

* Add fast sync block storage and process

* add fetch blocks timeout process

* Fix oops bug

* add timeoutQueue func

* Fix review bug

* Opz code format

* modify parallelFetchHeaders function

* modify select sync peer logic

* Del unused code

* add blocksTasks struct

* Modify block parallel download mode

* Opz code format

* Fix test case error

* opz code format

* Add fast sync peer err handle

* Fix test case err

* Fix review bugs

* Fix review bugs

* Fix review bugs

* Add test file

* Fix review bug

* Fix fetch headers stopHeader lost err

* Fix locate headers bug

* Opz code format

* Fix review bug