Update to the 72x72 TeamCity logo by default

Author: PeteGoo

tcslackbuildnotifier-core/src/main/java/slacknotifications/teamcity/settings/SlackNotificationMainConfig.java

@@ -17,7 +17,7 @@
 
 public class SlackNotificationMainConfig implements ChangeListener {
     public static final String DEFAULT_BOTNAME = "TeamCity";
-    public static final String DEFAULT_ICONURL = "https://raw.githubusercontent.com/PeteGoo/tcSlackBuildNotifier/master/docs/TeamCity.png";
+    public static final String DEFAULT_ICONURL = "https://raw.githubusercontent.com/PeteGoo/tcSlackBuildNotifier/master/docs/TeamCity72x72.png";
 
 
     private final FileWatcher myChangeObserver;

tcslackbuildnotifier-web-ui/src/main/resources/buildServerResources/SlackNotification/slackAdminSettings.jsp

@@ -69,7 +69,7 @@
                     <td>
                         <forms:textField name="iconUrl" value="${iconUrl}" style="width: 300px;" />
                         <span class="smallNote">The url of the icon to appear beside your bot. You can leave this as the default or customize it to a png file.</span>
-                        <span class="smallNote">The default is <b>https://raw.githubusercontent.com/PeteGoo/tcSlackBuildNotifier/master/docs/TeamCity.png</b>
+                        <span class="smallNote">The default is <b>https://raw.githubusercontent.com/PeteGoo/tcSlackBuildNotifier/master/docs/TeamCity72x72.png</b>
                     </td>
                 </tr>
                 <tr>