welcome has bootstrap, and cleaner grid

applications/welcome/views/default/index.html

@@ -20,7 +20,7 @@
 {{pass}}
 
 {{block right_sidebar}}
-{{=A(T("Administrative Interface"), _href=URL('admin','default','index'), _class='button',
+{{=A(T("Administrative Interface"), _href=URL('admin','default','index'), _class='btn',
      _style='margin-top: 1em;')}}
 <h6>{{=T("Don't know what to do?")}}</h6>
 <ul>