fix problem with folder pane width not persisting (in normal messenger layout)

and fix gravity problem with folder pane (250px is too much!)
thanks to <gonufer@yahoo.com> for the bug report.
r/sr=bienvenu

mailnews/base/resources/content/mail3PaneWindowVertLayout.xul

@@ -147,7 +147,7 @@ Rights Reserved.
     <vbox flex="1">
       <hbox id="mail3PaneVertLayoutBox" persist="collapsed height" flex="1">
         <vbox id="folderPaneBox" flex="1" autostretch="always" persist="width">
-          <tree id="folderTree" flex="1" style="min-width: 250px;" context="folderPaneContext" persist="collapsed width height"/>
+          <tree id="folderTree" flex="1" style="min-width: 100px;" context="folderPaneContext" persist="collapsed width height"/>
         </vbox>
 
         <splitter id="gray_vertical_splitter" collapse="before" persist="state">

mailnews/base/resources/content/messenger.xul

@@ -145,13 +145,13 @@ Rights Reserved.
   </toolbox>
 
   <hbox style="height:100px" flex="1">
-    <tree id="folderTree" style="min-width: 200px;" persist="height width" flex="1" context="folderPaneContext"/>
+    <tree id="folderTree" style="min-width: 100px;" persist="height width" flex="1" context="folderPaneContext"/>
       
     <splitter id="gray_vertical_splitter" collapse="before" persist="state">
       <grippy/>
     </splitter>
     
-    <vbox flex="1">
+    <vbox id="messengerBox" flex="1" persist="width">
       <vbox id="accountCentralBox" flex="1">
         <iframe name="accountCentralPane" flex="1" src="about:blank"/>
       </vbox>