playback: fix crash w/add to queue

Again, a two-fold problem:
- Was not properly giving the right StateAck to the state holder
- ShuffleOrder not properly handling the index given when adding to
queue internally

Resolves #727.

app/src/main/java/org/oxycblt/auxio/playback/state/PlaybackStateManager.kt

@@ -492,7 +492,7 @@ class PlaybackStateManagerImpl @Inject constructor() : PlaybackStateManager {
         } else {
             val stateHolder = stateHolder ?: return
             logD("Adding ${songs.size} songs to end of queue")
-            stateHolder.addToQueue(songs, StateAck.AddToQueue(stateMirror.index + 1, songs.size))
+            stateHolder.addToQueue(songs, StateAck.AddToQueue(queue.size, songs.size))
         }
     }
 

app/src/main/java/org/oxycblt/auxio/playback/system/BetterShuffleOrder.kt

@@ -69,7 +69,11 @@ class BetterShuffleOrder(private val shuffled: IntArray) : ShuffleOrder {
         }
 
         val newShuffled = IntArray(shuffled.size + insertionCount)
-        val pivot = indexInShuffled[insertionIndex]
+        val pivot: Int = if (insertionIndex < shuffled.size) {
+            indexInShuffled[insertionIndex]
+        } else {
+            indexInShuffled.size
+        }
         for (i in shuffled.indices) {
             var currentIndex = shuffled[i]
             if (currentIndex > insertionIndex) {