Actually fixed hotspot tooltip centering.

src/css/pannellum.css

@@ -296,7 +296,7 @@ div.tooltip:hover:after {
       border-style: solid;
       border-color: rgba(0,0,0,0.7) transparent transparent transparent;
       top: -12px;
-      left: 3px;
+      left: 0px;
 }
 
 #compass {

src/js/pannellum.js

@@ -497,8 +497,8 @@ function createHotSpots() {
             }
             span.innerHTML = hs.text;
             div.appendChild(span);
-            span.style.width = span.scrollWidth - 26 + 'px';
-            span.style.marginLeft = -(span.scrollWidth - 26) / 2 + 'px';
+            span.style.width = span.scrollWidth - 20 + 'px';
+            span.style.marginLeft = -(span.scrollWidth - 20) / 2 + 'px';
             span.style.marginTop = -span.scrollHeight - 12 + 'px';
             hs.div = div;
         });