GSS now works for Firefox!

* Change main.js to load gssweb.contentscript.js intead of navigator.gss.js

* Make some attempts to convert gssweb.contentscript.js into something that
  will work on both Chrome/Chromium and Firefox

* GSS Calls now work in firefox!
  ... authenticate doesn't yet work, because Firefox sends its content-type
       with a character encoding
       ("application/x-www-form-urlencoded; Charset: UTF-8) which causes the
       apache module problems with double-freeing memory, but that's a problem
       for a different commit.