Use server variables for client-size price calculation

public/static/signup.js

@@ -81,11 +81,11 @@ $(".list-group").on("click", ".rmpersonbtn", function () {
 function updateTotal() {
     totalcharge = $(".person-list-item[data-persontype=camper] input[data-name=firstname]").filter(function () {
         return $(this).val() != '';
-    }).length * 50.0;
+    }).length * prices.camp;
 
     totalcharge = totalcharge - $(".person-list-item[data-persontype=adult] input[data-name=days]:checked").filter(function () {
         return $(this).val() != '';
-    }).length * 10.0;
+    }).length * prices.adult_volunteer_daily_discount;
 
     // Add charge for adult shirts
     totalcharge = totalcharge + $(".person-list-item[data-persontype=adult]").filter(function () {