add some logic tools

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@6189 d0543943-73ff-0310-b7d9-9358b9ac24b2

conf/modules.conf.xml

@@ -36,6 +36,7 @@
     <load module="mod_commands"/>
     <load module="mod_conference"/>
     <load module="mod_dptools"/>
+    <load module="mod_expr"/>
     <load module="mod_fifo"/>
     <load module="mod_voicemail"/>
     <load module="mod_limit"/>