major rewrite, reorg of blockpool + new features

- 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

blockpool/config_test.go

@@ -0,0 +1,40 @@
+package blockpool
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/blockpool/test"
+)
+
+func TestBlockPoolConfig(t *testing.T) {
+	test.LogInit()
+	blockPool := &BlockPool{Config: &Config{}}
+	blockPool.Start()
+	c := blockPool.Config
+	test.CheckInt("BlockHashesBatchSize", c.BlockHashesBatchSize, blockHashesBatchSize, t)
+	test.CheckInt("BlockBatchSize", c.BlockBatchSize, blockBatchSize, t)
+	test.CheckInt("BlocksRequestRepetition", c.BlocksRequestRepetition, blocksRequestRepetition, t)
+	test.CheckInt("BlocksRequestMaxIdleRounds", c.BlocksRequestMaxIdleRounds, blocksRequestMaxIdleRounds, t)
+	test.CheckDuration("BlockHashesRequestInterval", c.BlockHashesRequestInterval, blockHashesRequestInterval, t)
+	test.CheckDuration("BlocksRequestInterval", c.BlocksRequestInterval, blocksRequestInterval, t)
+	test.CheckDuration("BlockHashesTimeout", c.BlockHashesTimeout, blockHashesTimeout, t)
+	test.CheckDuration("BlocksTimeout", c.BlocksTimeout, blocksTimeout, t)
+}
+
+func TestBlockPoolOverrideConfig(t *testing.T) {
+	test.LogInit()
+	blockPool := &BlockPool{Config: &Config{}}
+	c := &Config{128, 32, 1, 0, 300 * time.Millisecond, 100 * time.Millisecond, 90 * time.Second, 0}
+
+	blockPool.Config = c
+	blockPool.Start()
+	test.CheckInt("BlockHashesBatchSize", c.BlockHashesBatchSize, 128, t)
+	test.CheckInt("BlockBatchSize", c.BlockBatchSize, 32, t)
+	test.CheckInt("BlocksRequestRepetition", c.BlocksRequestRepetition, blocksRequestRepetition, t)
+	test.CheckInt("BlocksRequestMaxIdleRounds", c.BlocksRequestMaxIdleRounds, blocksRequestMaxIdleRounds, t)
+	test.CheckDuration("BlockHashesRequestInterval", c.BlockHashesRequestInterval, 300*time.Millisecond, t)
+	test.CheckDuration("BlocksRequestInterval", c.BlocksRequestInterval, 100*time.Millisecond, t)
+	test.CheckDuration("BlockHashesTimeout", c.BlockHashesTimeout, 90*time.Second, t)
+	test.CheckDuration("BlocksTimeout", c.BlocksTimeout, blocksTimeout, t)
+}