Replace <link rel="import"> with <import>

This CL is just a search-and-replace.

R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/694423002

examples/city-list/city-list.sky

@@ -3,11 +3,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 -->
-<link rel="import"
-      href="../../framework/sky-element/sky-element.sky"
-      as="SkyElement" />
-<link rel="import" href="city-data-service.sky" as="CityDataService" />
-<link rel="import" href="city-sequence.sky" as="CitySequence" />
+<import src="../../framework/sky-element/sky-element.sky" as="SkyElement" />
+<import src="city-data-service.sky" as="CityDataService" />
+<import src="city-sequence.sky" as="CitySequence" />
 
 <template>  
   <style>

examples/city-list/index.sky

@@ -9,7 +9,7 @@
 <meta charset="utf-8">
 <meta name="viewport"
       content="initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=yes, width=device-width">
-<link rel="import" href="city-list.sky" />
+<import src="city-list.sky" />
 <style>
 html, body {
     margin: 0;