[IMP] continue refactoring timeago.js, following the conversation on …

…this pull request: #83

- remove bad usage of global variable stringAndNumber
- use a consistent name for the substitute() function which was actully not substituing anything anymore

jquery.timeago.js

@@ -69,24 +69,24 @@
       var days = hours / 24;
       var years = days / 365;
 
-      function substitute(stringOrFunction, number) {
+      function convert(stringOrFunction, number) {
         var string = $.isFunction(stringOrFunction) ? stringOrFunction(number, distanceMillis) : stringOrFunction;
 
         // return the proper string and the numeric value that goes in it
-        return stringAndNumber = {'string': string, 'value': ($l.numbers && $l.numbers[number]) || number};
+        return {'string': string, 'value': ($l.numbers && $l.numbers[number]) || number};
       }
 
-      var words = seconds < 45 && substitute($l.seconds, Math.round(seconds)) ||
-        seconds < 90 && substitute($l.minute, 1) ||
-        minutes < 45 && substitute($l.minutes, Math.round(minutes)) ||
-        minutes < 90 && substitute($l.hour, 1) ||
-        hours < 24 && substitute($l.hours, Math.round(hours)) ||
-        hours < 42 && substitute($l.day, 1) ||
-        days < 30 && substitute($l.days, Math.round(days)) ||
-        days < 45 && substitute($l.month, 1) ||
-        days < 365 && substitute($l.months, Math.round(days / 30)) ||
-        years < 1.5 && substitute($l.year, 1) ||
-        substitute($l.years, Math.round(years));
+      var stringAndNumber = seconds < 45 && convert($l.seconds, Math.round(seconds)) ||
+        seconds < 90 && convert($l.minute, 1) ||
+        minutes < 45 && convert($l.minutes, Math.round(minutes)) ||
+        minutes < 90 && convert($l.hour, 1) ||
+        hours < 24 && convert($l.hours, Math.round(hours)) ||
+        hours < 42 && convert($l.day, 1) ||
+        days < 30 && convert($l.days, Math.round(days)) ||
+        days < 45 && convert($l.month, 1) ||
+        days < 365 && convert($l.months, Math.round(days / 30)) ||
+        years < 1.5 && convert($l.year, 1) ||
+        convert($l.years, Math.round(years));
 
       var string = stringAndNumber.string;
       var value = stringAndNumber.value;