.osx: Increase sound quality for Bluetooth headphones/headsets

This has the same effect as setting Bluetooth Explorer → Utilities →
Special Options → Minimum bitpool to `40`. See
http://scott.dier.name/2009/10/osx-snow-leopard-a2dp.html.

.osx

@@ -44,7 +44,7 @@ defaults write NSGlobalDomain NSDisableAutomaticTermination -bool true
 #echo "0x08000100:0" > ~/.CFUserTextEncoding
 
 ###############################################################################
-# Trackpad, mouse, keyboard, and input                                        #
+# Trackpad, mouse, keyboard, Bluetooth accessories, and input                 #
 ###############################################################################
 
 # Trackpad: enable tap to click for this user and for the login screen
@@ -66,6 +66,9 @@ defaults write com.apple.driver.AppleBluetoothMultitouch.trackpad TrackpadThreeF
 # Disable “natural” (Lion-style) scrolling
 defaults write NSGlobalDomain com.apple.swipescrolldirection -bool false
 
+# Increase sound quality for Bluetooth headphones/headsets
+defaults write com.apple.BluetoothAudioAgent "Apple Bitpool Min (editable)" -int 40
+
 # Enable full keyboard access for all controls
 # (e.g. enable Tab in modal dialogs)
 defaults write NSGlobalDomain AppleKeyboardUIMode -int 3