rpc rewrite: control RPCs using gRPC + separate RPC for data transfer

transport/ssh: update go-netssh to new version
    => supports CloseWrite and Deadlines
    => build: require Go 1.11 (netssh requires it)

rpc/dataconn/frameconn/frameconn_test.go

@@ -0,0 +1,22 @@
+package frameconn
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIsPublicFrameType(t *testing.T) {
+	for i := uint32(0); i < 256; i++ {
+		i := i
+		t.Run(fmt.Sprintf("^%d", i), func(t *testing.T) {
+			assert.False(t, IsPublicFrameType(^i))
+		})
+	}
+	assert.True(t, IsPublicFrameType(0))
+	assert.True(t, IsPublicFrameType(1))
+	assert.True(t, IsPublicFrameType(255))
+	assert.False(t, IsPublicFrameType(rstFrameType))
+}
+