Add block fast sync function (#1104)

Add block fast sync function (#1104)

* Add block headers handler for fast sync

* Add testnet checkpoint

* Add debug info

* Fix GetHeadersMessage bug

* Add debug info

* Fix HeadersMessage bug

* Add HeadersMessage handler

* Fast sync call BlockRequestWorker download block

* Add debug info for measure time

* Add getBlocks for fast sync

* Fix code logic errors

* Del unused variable headersFirstMode

* Fix hash string compare error

* Fix code logic errors

* Fix blocksSend logic error

* Optimize log printing

* Add max blocksMsg package size limit

* Modify fast sync node selection logic

* Fix multi checkpoint fast sync error

* Del unused code prevGetHdrsMtx

* Add fast sync txs merkle root check

* Add fast sync complete new status broadcast

* Change variable hash format

* edit the code format

* delete the unused checkpoint

* edit netsync message byte

* Fix Duplicate Byte BlockRequestMessage

* Add testnet checkpoint

* tmp save

* edit the handle logic

* edit the fast sync

* move tx process out of blockKeeper

* elegant the message

* elegant the peer.go

* elegant block_keeper

* elegant the block_fetcher

* fix api node info bug

* delete unused data

* edit the tx_keeper

* edit ban method

* make sure both size sync tx

* add response bool on every send

* handle all the peer dc

* merge with dev

* fix bug on merge with dev

* add max block peer msg limit

* limit the max send block size

* fix the web wallet display bug

* fix hand shake timepout error

* fix logic if statement

* edit the services flag bug

* add error message log

* edit blocks/headers, marshal/unmarshal

* edit the message field name

* fix sync logic bug

* fix sync bug

* fix a code logic error