License of sounds
-----------------

Glass breaking sounds (CC BY 3.0):
   1: http://www.freesound.org/people/cmusounddesign/sounds/71947/
   2: http://www.freesound.org/people/Tomlija/sounds/97669/
   3: http://www.freesound.org/people/lsprice/sounds/88808/

Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)
http://creativecommons.org/licenses/by-sa/3.0/

default_tool_breaks.ogg by EdgardEdition (CC BY 3.0), http://www.freesound.org/people/EdgardEdition

Mito551 (sounds) (CC BY-SA 3.0):
  default_dig_choppy.ogg
  default_dig_cracky.ogg
  default_dig_crumbly.1.ogg
  default_dig_crumbly.2.ogg
  default_dig_oddly_breakable_by_hand.ogg
  default_dug_node.1.ogg
  default_dug_node.2.ogg
  default_grass_footstep.1.ogg
  default_grass_footstep.2.ogg
  default_grass_footstep.3.ogg
  default_gravel_footstep.1.ogg
  default_gravel_footstep.2.ogg
  default_gravel_footstep.3.ogg
  default_gravel_footstep.4.ogg
  default_grass_footstep.1.ogg
  default_place_node.1.ogg
  default_place_node.2.ogg
  default_place_node.3.ogg
  default_place_node_hard.1.ogg
  default_place_node_hard.2.ogg
  default_snow_footstep.1.ogg
  default_snow_footstep.2.ogg
  default_hard_footstep.1.ogg
  default_hard_footstep.2.ogg
  default_hard_footstep.3.ogg
  default_sand_footstep.1.ogg
  default_sand_footstep.2.ogg
  default_wood_footstep.1.ogg
  default_wood_footstep.2.ogg
  default_dirt_footstep.1.ogg
  default_dirt_footstep.2.ogg
  default_glass_footstep.ogg