travis: test against 1.8.x

.travis.yml

@@ -1,7 +1,8 @@
 language: go
 go:
-    - 1.6.3
-    - 1.7.4
+    - 1.6.x
+    - 1.7.x
+    - 1.8.x
 sudo: false
 install:
     - go get -v github.com/alecthomas/gometalinter

spew/format_test.go

@@ -1536,14 +1536,14 @@ func TestPrintSortedKeys(t *testing.T) {
 		t.Errorf("Sorted keys mismatch 3:\n  %v %v", s, expected)
 	}
 
-	s = cfg.Sprint(map[testStruct]int{testStruct{1}: 1, testStruct{3}: 3, testStruct{2}: 2})
+	s = cfg.Sprint(map[testStruct]int{{1}: 1, {3}: 3, {2}: 2})
 	expected = "map[ts.1:1 ts.2:2 ts.3:3]"
 	if s != expected {
 		t.Errorf("Sorted keys mismatch 4:\n  %v %v", s, expected)
 	}
 
 	if !spew.UnsafeDisabled {
-		s = cfg.Sprint(map[testStructP]int{testStructP{1}: 1, testStructP{3}: 3, testStructP{2}: 2})
+		s = cfg.Sprint(map[testStructP]int{{1}: 1, {3}: 3, {2}: 2})
 		expected = "map[ts.1:1 ts.2:2 ts.3:3]"
 		if s != expected {
 			t.Errorf("Sorted keys mismatch 5:\n  %v %v", s, expected)