sort: rename helpers: s/Sort// in sort.Sort[Float64s|Ints|Strings]

Includes 'sorthelpers' gofix and updates to tree.

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/4631098
diff --git a/src/pkg/exp/template/exec_test.go b/src/pkg/exp/template/exec_test.go
index 8992299..86b958e 100644
--- a/src/pkg/exp/template/exec_test.go
+++ b/src/pkg/exp/template/exec_test.go
@@ -108,7 +108,7 @@
 		keys[i] = k
 		i++
 	}
-	sort.SortStrings(keys)
+	sort.Strings(keys)
 	return keys
 }