Added checks for file api support

A browser without file api support, like IE9, throws an error when anything but the constructor is called, this change will fix all of the scenarios.

js/fileinput.js

@@ -675,6 +675,10 @@
     }
 
     $.fn.fileinput = function (options) {
+        if (!hasFileAPISupport()) {
+          return;
+        }
+        
         return this.each(function () {
             var $this = $(this), data = $this.data('fileinput')
             if (!data) {
@@ -688,6 +692,10 @@
 
     //FileInput plugin definition
     $.fn.fileinput = function (option) {
+        if (!hasFileAPISupport()) {
+          return;
+        }
+        
         var args = Array.apply(null, arguments);
         args.shift();
         return this.each(function () {
@@ -771,4 +779,4 @@
         }
     });
 
-})(window.jQuery);
+})(window.jQuery);