docs and pgp version

pom.xml

@@ -297,7 +297,7 @@
                     <plugin>
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-gpg-plugin</artifactId>
-                        <version>1.5</version>
+                        <version>1.6</version>
                         <executions>
                             <execution>
                                 <phase>verify</phase>

webmagic-core/src/main/java/us/codecraft/webmagic/Site.java

@@ -320,6 +320,7 @@ public class Site {
      * Disable it to ignore all cookie fields and stay clean.
      * Warning: Set cookie will still NOT work if disableCookieManagement is true.
      * @param disableCookieManagement disableCookieManagement
+     * @return this
      */
     public Site setDisableCookieManagement(boolean disableCookieManagement) {
         this.disableCookieManagement = disableCookieManagement;