Sorttable: avoid registering init multiple times

The script pre-dates jQuery usage so it's understandable the amount of
workarounds and boilerplate that were needed back then to run code at startup.
They are not necessary anymore and this commit removes them which also avoids to
register extra listeners to run the init callback.

pootle/static/js/vendor/sorttable.js

@@ -23,13 +23,6 @@
 
 sorttable = {
   init: function() {
-    // quit if this function has already been called
-    if (arguments.callee.done) return;
-    // flag this function so we don't do the same thing twice
-    arguments.callee.done = true;
-    // kill the timer
-    if (_timer) clearInterval(_timer);
-
     if (!document.createElement || !document.getElementsByTagName) return;
 
     sorttable.DATE_RE = /^(\d\d?)[\/\.-](\d\d?)[\/\.-]((\d\d)?\d\d)$/;
@@ -401,35 +394,7 @@ sorttable = {
 
 // Dean Edwards/Matthias Miller/John Resig
 
-/* for Mozilla/Opera9 */
-if (document.addEventListener) {
-    document.addEventListener("DOMContentLoaded", sorttable.init, false);
-}
-
-/* for Internet Explorer */
-/*@cc_on @*/
-/*@if (@_win32)
-    var dummy = (location.protocol == "https:") ? "//:" : "javascript:void(0)";
-    document.write('<script id=__ie_onload defer src="' + dummy + '"><\/script>');
-    var script = document.getElementById("__ie_onload");
-    script.onreadystatechange = function() {
-        if (this.readyState == "complete") {
-            sorttable.init(); // call the onload handler
-        }
-    };
-/*@end @*/
-
-/* for Safari */
-if (/WebKit/i.test(navigator.userAgent)) { // sniff
-    var _timer = setInterval(function() {
-        if (/loaded|complete/.test(document.readyState)) {
-            sorttable.init(); // call the onload handler
-        }
-    }, 10);
-}
-
-/* for other browsers */
-window.onload = sorttable.init;
+document.addEventListener("DOMContentLoaded", sorttable.init, false);
 
 // written by Dean Edwards, 2005
 // with input from Tino Zijdel, Matthias Miller, Diego Perini