- Convert the list of URI handlers to use the linked list macros. While doing

- Convert the list of URI handlers to use the linked list macros.  While doing
  this, implementing locking of this list to make it thread-safe.

- Add a "redirect" option to http.conf that allows redirecting one URI to
  another.  I was inspired to do this while playing with the Asterisk GUI.  I
  got tired of typing this URL to get to the GUI:

     http://localhost:8088/asterisk/static/config/cfgadvanced.html

  So, now I have the following line in http.conf:

     redirect=/=/asterisk/static/config/cfgadvanced.html

  Now, I can type the following into my browser and go to the GUI:

     http://localhost:8088

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@48930 65c4cc65-6c06-0410-ace0-fbb531ad65f3