Add offline mode for Xars

Author: adamretter

src/main/xar-resources/data/exist-building/exist-building.xml

@@ -234,6 +234,14 @@
               <para>Specify the certificate for signing of Mac <code>.app</code> and <code>.DMG</code> files (only on Mac platforms).</para>
             </entry>
           </row>
+          <row>
+            <entry>
+              <para><code>-Dxar.resolve.offline=true</code></para>
+            </entry>
+            <entry>
+              <para>Do not attempt to download the latest version of any EXPath Packages which are set to be auto-deployed. Useful for offline working; inferred by Maven's `-O` option.</para>
+            </entry>
+          </row>
           <row>
             <entry>
               <para><code>-DskipTests</code></para>