add new preference for automatically downloading mail on biff

mailnews/base/prefs/resources/content/am-server.xul

@@ -39,6 +39,8 @@
                         type="checkbox"/>&biffStart.label;
             <html:input name="server.biffMinutes" type="text" size="3"/>
             &biffEnd.label;
+  <html:div><html:input name="server.downloadOnBiff"
+                        type="checkbox"/>&downloadOnBiff.label;</html:div>
   </html:div>
   </box>
   <tabcontrol flex="100%">

mailnews/base/prefs/resources/locale/en-US/am-server-top.dtd

@@ -20,6 +20,7 @@
 <!ENTITY biffEnd.label "minutes">
 <!ENTITY leaveOnServer.label "Leave messages on server">
 <!ENTITY deleteOnServer.label "Delete messages on server when deleted locally.">
+<!ENTITY downloadOnBiff.label "Automatically download any new messages">
 <!ENTITY emptyTrashOnExit.label "Empty Trash on Exit">
 <!ENTITY hostname.label "Server Hostname">
 <!ENTITY username.label "Your Login Name">

suite/locales/en-US/chrome/mailnews/pref/am-server-top.dtd

@@ -20,6 +20,7 @@
 <!ENTITY biffEnd.label "minutes">
 <!ENTITY leaveOnServer.label "Leave messages on server">
 <!ENTITY deleteOnServer.label "Delete messages on server when deleted locally.">
+<!ENTITY downloadOnBiff.label "Automatically download any new messages">
 <!ENTITY emptyTrashOnExit.label "Empty Trash on Exit">
 <!ENTITY hostname.label "Server Hostname">
 <!ENTITY username.label "Your Login Name">