schema/nodeattr: new leaf package for permanode attributes

All the attributes from pkg/importer/attrs.go should eventually move here.

Change-Id: I252749ca32fdb0f367dfa906e728d0a679e8eb5b

pkg/schema/nodeattr/nodeattr.go

@@ -0,0 +1,26 @@
+/*
+Copyright 2014 The Camlistore Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package nodeattr contains constants for permanode attribute names.
+package nodeattr
+
+const (
+	// DateCreated is http://schema.org/dateCreated: The date on
+	// which an item was created, in RFC 3339 format (with
+	// Camlistore's addition that zone -00:01 means localtime:
+	// unknown timezone).
+	DateCreated = "dateCreated"
+)