Fix NaNs problem #110

The problem was in precedence of ternary operator and + sign.

Merge branch 'fix-nan'

media/js/discipline/editStructure.js

@@ -19,7 +19,7 @@ $(document).ready(function () {
         sum: function (asText) {
             var sum = 0;
             this.each(function () {
-                sum += parseInt(0 + asText ? $(this).text() : $(this).val())
+                sum += parseInt(0 + ( asText ? $(this).text() : $(this).val() ))
             });
             return sum;
         },