Asset changes and updates

* Add new music for the City Skyway (to become Voxel Village) track
* Add a pack of house models for use in the Kapman Island Resort track
* Update the PacmanFinal model with an armature, and change its animation

library_custom/HousesPack/licenses.txt

+Files: roof_3.jpg
+Copyright: Public Domain ???? by ????
+License: CC0
+Comment: Source no longer available but cited as http://tellim.com/texture_cd/texture/building/roof/roof04.jpg
+
+Files:
+ roof_3_glossy.jpg
+ roof_3_nm.jpg
+Copyright:
+ Public Domain ???? by ????
+ Copyright 2018 by Sven Andreas Belting
+License: CC-BY-SA 4.0
+Comment: Source no longer available but cited as http://tellim.com/texture_cd/texture/building/roof/roof04.jpg
+
+Files: gray_bricks.png
+Source: Grayscale version of sand_stone.png from https://opengameart.org/content/textures-stk
+Copyright: Dakal
+License: CC By_SA 3.0+

library_custom/README.md

-# A list of sources for the contents of the library_custom directory
-* Racetrack/ : https://opengameart.org/content/modular-racetrack-3d-models
-* lowpoly_building/ : https://opengameart.org/content/low-poly-skyscraper
-* dist/ : https://opengameart.org/content/voxel-buildings
-* skyboxes/ : https://opengameart.org/content/space-skyboxes
-* skateboard/ : https://opengameart.org/content/skateboard
-* steering-wheel/ : https://opengameart.org/content/steering-wheel
-* traffic-cone/ : https://opengameart.org/content/traffic-cone
-
-* PacmanFinal.blend: https://opengameart.org/content/marbleman-gobbler-with-animation
-* ske.blend: https://opengameart.org/content/ske-supertux3d
-* stilagmate.blend: https://opengameart.org/content/stilagmate-supertux3d
-* StreetSigns.blend: https://opengameart.org/content/basic-street-signs
-
-## Usage
-Append to any track, instead of linking, as these files are not shipped with SuperTuxKart. In the future, it is possible to set up these items as custom library nodes that are shipped on a per-track basis.
+# A list of sources for the contents of the library_custom directory
+Unless otherwise stated, all assets listed below are under the same license as their original sources.
+
+* Racetrack/ : https://opengameart.org/content/modular-racetrack-3d-models
+* lowpoly_building/ : https://opengameart.org/content/low-poly-skyscraper
+* dist/ : https://opengameart.org/content/voxel-buildings
+* skyboxes/ : https://opengameart.org/content/space-skyboxes
+* skateboard/ : https://opengameart.org/content/skateboard
+* steering-wheel/ : https://opengameart.org/content/steering-wheel
+* traffic-cone/ : https://opengameart.org/content/traffic-cone
+
+* PacmanFinal.blend: https://opengameart.org/content/marbleman-gobbler-with-animation, modified to include an armature and different animations
+* ske.blend: https://opengameart.org/content/ske-supertux3d
+* stilagmate.blend: https://opengameart.org/content/stilagmate-supertux3d
+* StreetSigns.blend: https://opengameart.org/content/basic-street-signs
+* HousesPack/HousesPack.blend: Derived from https://opengameart.org/content/houses-pack-low-poly-v02, modified to include textures
+
+## Usage
+Append to any track, instead of linking, as these files are not shipped with SuperTuxKart. In the future, it is possible to set up these items as custom library nodes that are shipped on a per-track basis.

music/random-race.music

+<?xml version="1.0"?>
+<music title    = "Arcade Racing"
+       composer = "rezoner"
+       file     = "random-race.ogg"/>