Bucky/fix evidence halt (#34)

* consensus: createProposalBlock function

* blockExecutor.CreateProposalBlock

- factored out of consensus pkg into a method on blockExec
- new private interfaces for mempool ("txNotifier") and evpool with one function each
- consensus tests still require more mempool methods

* failing test for CreateProposalBlock

* Fix bug in include evidece into block

* evidence: change maxBytes to maxSize

* MaxEvidencePerBlock

- changed to return both the max number and the max bytes
- preparation for #2590

* changelog

* fix linter

* Fix from review

Co-Authored-By: ebuchman <ethan@coinculture.info>

state/validation.go

@@ -133,10 +133,11 @@ func validateBlock(stateDB dbm.DB, state State, block *types.Block) error {
 	}
 
 	// Limit the amount of evidence
-	maxEvidenceBytes := types.MaxEvidenceBytesPerBlock(state.ConsensusParams.BlockSize.MaxBytes)
-	evidenceBytes := int64(len(block.Evidence.Evidence)) * types.MaxEvidenceBytes
-	if evidenceBytes > maxEvidenceBytes {
-		return types.NewErrEvidenceOverflow(maxEvidenceBytes, evidenceBytes)
+	maxNumEvidence, _ := types.MaxEvidencePerBlock(state.ConsensusParams.BlockSize.MaxBytes)
+	numEvidence := int64(len(block.Evidence.Evidence))
+	if numEvidence > maxNumEvidence {
+		return types.NewErrEvidenceOverflow(maxNumEvidence, numEvidence)
+
 	}
 
 	// Validate all evidence.