Fix to helperNumberLayer dimensions and Next arrow, related to usablica#26

Author: afshinm

intro.js

@@ -268,7 +268,7 @@
 
       nextTooltipButton.className = "introjs-nextbutton";
       nextTooltipButton.href = "javascript:void(0);";
-      nextTooltipButton.innerHTML = "Next →";
+      nextTooltipButton.innerHTML = "Next →";
 
       skipTooltipButton.onclick = function() {
         _exitIntro.call(self, self._targetElement);

introjs.css

@@ -34,7 +34,6 @@
   top: -16px;
   left: -16px;
   z-index: 9999999999 !important;
-  width: 20px;
   padding: 2px;
   font-family: Arial, verdana, tahoma;
   font-size: 13px;
@@ -49,6 +48,9 @@
   background:     -ms-linear-gradient(top, #ff3019 0%, #cf0404 100%); /* IE10+ */
   background:      -o-linear-gradient(top, #ff3019 0%, #cf0404 100%); /* Opera 11.10+ */
   background:         linear-gradient(to bottom, #ff3019 0%, #cf0404 100%);  /* W3C */
+  width: 20px;
+  height:20px;
+  line-height: 20px;
   border: 3px solid white;
   border-radius: 50%;
   filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ff3019', endColorstr='#cf0404', GradientType=0); /* IE6-9 */