Fixed hotspot tooltip centering.

src/js/pannellum.js

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