Remove track element during destroy only if it was created by glider

It's not necessary to remove the track element during destroy if it was not created by glider but by the user (using skipTrack: true). Additionally, the statement assigning innerHTML to outerHTML causes problems with Content Security Policy without 'unsafe-inline' keyword or similar workaround.

glider.js

@@ -566,8 +566,10 @@
         /^glider/.test(className) && ele.classList.remove(className)
       })
     }
-    // remove track
-    replace.children[0].outerHTML = replace.children[0].innerHTML
+    // remove track if it was created by glider
+    if (!_.opt.skipTrack) {
+      replace.children[0].outerHTML = replace.children[0].innerHTML
+    }
     clear(replace);
     [].forEach.call(replace.getElementsByTagName('*'), clear)
     _.ele.parentNode.replaceChild(replace, _.ele)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "glider-js",
-  "version": "1.7.7",
+  "version": "1.7.8",
   "description": "A fast, lightweight carousel alternative",
   "main": "glider.js",
   "directories": {