conesnsu: follow up to removing some consensus params (#2427)

* follow up to removing some consensus params Refs #2382
* change args type to int64 in state#makeParams
* make valsCount and evidenceCount ints again
* MaxEvidenceBytesPerBlock: include magic number in godoc
* [spec] creating a proposal
* test state#TxFilter
* panic if MaxDataBytes is less than 0
* fixes after review
* use amino#UvarintSize to calculate overhead
0c74291f3b/encoder.go (L85-L90)
* avoid cyclic imports
* you can do better Go, come on
* remove testdouble package

mempool/mempool_test.go

@@ -90,7 +90,7 @@ func TestReapMaxBytesMaxGas(t *testing.T) {
 	// each tx has 20 bytes + amino overhead = 21 bytes, 1 gas
 	tests := []struct {
 		numTxsToCreate int
-		maxBytes       int
+		maxBytes       int64
 		maxGas         int64
 		expectedNumTxs int
 	}{