> PlayerSound script (requires ground recognition)

This reverts commit 07a1f18d1b.

+ Particle: Magnet Sparks
+ Texture: Cargo Container (Metal) (for the crane)

+ Updated Character textures (requires updated character FBX with proper UV)
+ Textures: Car trailer & engine
+ Object: Car Trailer (modified their UVs for easier texturing)
+ Shader: Laser PUSH (unused for now)

CHANGES:
> Created child objects for "Laser Holder PULL" for testing two-line and multiple-line line renderer.

KNOWN ISSUES:
> Using 3 or more line renderers significantly reduces frame rate. Please don't use multiple line renderers unless
it can be optimized.

added pully functionality,
fixed black texture bug.

-fixed bugs

+ Texture: Mine cart
+ Texture: Concrete
+ Texture: Rust (for crane)
+ Texture: Building
+ Texture: Metal (2 x variants)
+ Terrain Texture: Cracked Sand
+ Skybox: "Junk Sky" (Purple)
+ Texture: Ben's metal object textures (color still not changed as requested)
+ Added stair path near the edge of the scaffold

CHANGED:
> All objects have their textures (movable object textures still need changes)
> Seperated Pully system into two FBX objects: Pully Platform and Pully Extension
> Re-positioned some of the tutorial signs
> Changed the tutorial sign for Pull/Push. It no longer shows the LT button.
> Placed some fences on the building to prevent "flying-platform" exploits.
> Placed several invisible walls next to the above mentioned fences.

REMOVED:
- Redundant placeholder textures for characters and objects
- Several metal beams that were placed in the mine carts
- Static mine carts before the fence (replaced by "Mine Cart Movable" prefab)
- Old Pully System FBX (was not unwrapped before)

+ Textures: Pull & Push Brothers including default face texture.
+ Texture: Cargo Container
+ Texture: Scaffolds (Default, Wall-A and Wall-B)
+ Unity Package: Sky5x (Skybox collection)

CHANGED:
> Temporarily using a skybox from the sky5x package

NOTE 2: If you require me to revert my Unity version and save the scene for v5.1.2f1 compatibility, let me know ASAP.

+ Created a new Unity scene named "MainLevel.unity" in the Scenes folder.
  (All prefab objects are in this scene.)

+ Most of the essential structures in the level have been set up.
  More props for purely aesthetic will be added later.

+ MainLevel scene uses "InputManager.asset" downloaded via Facebook chat on 29.8.15

+ Added objects from original Maya scaffold scene as seperate objects for prefab use.
+ Created a new folder named "Custom Meshes". Contains meshes for appropriate collision for certain objects
+ Added README text files to the following folders: Objects, Textures, ToonShading.
 (Certain README text files contain specific information including naming conventions. Please read for more info.)

KNOWN ISSUES:
- Interactable objects with the "moveable" tag and using a Mesh Collider have no effect on the magnet rods.
  When using a default RigidBody on such objects, the following console error occurs:

  "Non-convex MeshCollider with non-kinematic Rigidbody is no longer supported in Unity 5"
  "If you want to use a non-convex mesh, either make the Rigidbody kinematic or remove the rigidbody component"

- The above error does not occur when "Is Kinematic" is ticked in the
  Rigidbody component; however the object cannot interact with the magnet rod.