fix a regression that broke simple audio play/pause usage

@see goldfire/howler.js#1102

CHANGELOG

@@ -2,6 +2,7 @@ Version History
 ---------------
 6.3.0
 * Audio : audio core update (2.1.0) that mostly improve auto audio unlock on latest (non-mobile) browser versions
+* Audio : fix a regression that broke simple play/pause usage
 * Color : fix alpha value not being properly clamped (leading to issue in WebGL mode when passing the glArray buffer)
 * Debug : fix wrong bounding box drawing position for nested containers
 * Renderable : added support for rendering mask (in both Canvas and WebGL mode), allowing to use any me.Shape object as a mask

src/vendors/howler.core.js

@@ -719,6 +719,24 @@
       } else if (typeof sprite === 'undefined') {
         // Use the default sound sprite (plays the full audio length).
         sprite = '__default';
+
+        // Check if there is a single paused sound that isn't ended.
+        // If there is, play that sound. If not, continue as usual.
+        if (!self._playLock) {
+          var num = 0;
+          for (var i=0; i<self._sounds.length; i++) {
+            if (self._sounds[i]._paused && !self._sounds[i]._ended) {
+              num++;
+              id = self._sounds[i]._id;
+            }
+          }
+
+          if (num === 1) {
+            sprite = null;
+          } else {
+            id = null;
+          }
+        }
       }
 
       // Get the selected node, or get one from the pool.