Minor new additions for v20 (#147)

* Moved TMs/ TRs and HMs into their own handlers
* Improved Plugin Error Message
* Added sound effect when picking berries
* Allow player to always see quantity when buying items
* Trainers now require a Mega Ring item in their items (in trainers.txt) to Mega Evolve

Data/Scripts/011_Battle/001_Battle/001_Battle.rb

@@ -54,6 +54,7 @@ class Battle
   attr_reader   :player           # Player trainer (or array of trainers)
   attr_reader   :opponent         # Opponent trainer (or array of trainers)
   attr_accessor :items            # Items held by opponents
+  attr_accessor :ally_items       # Items held by allies
   attr_accessor :endSpeeches
   attr_accessor :endSpeechesWin
   attr_accessor :party1starts     # Array of start indexes for each player-side trainer's party
@@ -119,6 +120,7 @@ class Battle
     @player            = player     # Array of Player/NPCTrainer objects, or nil
     @opponent          = opponent   # Array of NPCTrainer objects, or nil
     @items             = nil
+    @ally_items        = nil        # Array of items held by ally. This is just used for Mega Evolution for now.
     @endSpeeches       = []
     @endSpeechesWin    = []
     @party1            = p1
@@ -167,6 +169,8 @@ class Battle
     else
       @struggle = Move::Struggle.new(self, nil)
     end
+    @mega_rings = []
+    GameData::Item.each { |item| @mega_rings.push(item.id) if item.has_flag?("MegaRing") }
   end
 
   #=============================================================================
@@ -259,8 +263,14 @@ class Battle
   end
 
   def pbGetOwnerItems(idxBattler)
-    return [] if !@items || !opposes?(idxBattler)
-    return @items[pbGetOwnerIndexFromBattlerIndex(idxBattler)]
+    if opposes?(idxBattler)
+      return [] if !@items
+      return @items[pbGetOwnerIndexFromBattlerIndex(idxBattler)]
+    else
+      return [] if !@ally_items
+      return @ally_items[pbGetOwnerIndexFromBattlerIndex(idxBattler)]
+    end
+    return []
   end
 
   # Returns whether the battler in position idxBattler is owned by the same