Add ID_CAP_MEDIALIB_PHOTO for wp8

Author: devgeeks

plugin.xml

@@ -60,6 +60,10 @@
                 <param name="onload" value="true" />
             </feature>
         </config-file>
+        
+        <config-file target="Properties/WMAppManifest.xml" parent="/Deployment/App/Capabilities">
+            <Capability Name="ID_CAP_MEDIALIB_PHOTO" />
+        </config-file>
 
         <source-file src="src/wp8/Canvas2ImagePlugin.cs" />
     </platform>