A loader for loading a .tga resource. 
		TGA is a raster graphics, image file format.
		
		// instantiate a loader
		var loader = new THREE.TGALoader();
		// load a resource
		var texture = loader.load(
			// resource URL
			'textures/crate_grey8.tga'
			// called when loading is completed
			function ( texture ) {
				console.log( 'Texture is loaded' );
			},
			// called when the loading is in progresses
			function ( xhr ) {
				console.log( ( xhr.loaded / xhr.total * 100 ) + '% loaded' );
			},
			// called when the loading failes
			function ( error ) {
				console.log( 'An error happened' );
			}
		);
		var material = new THREE.MeshPhongMaterial( {
			color: 0xffffff,
			map: texture
		} );
		
		[example:webgl_loader_texture_tga]
		[page:LoadingManager manager] — The [page:LoadingManager loadingManager] for the loader to use. Default is [page:LoadingManager THREE.DefaultLoadingManager].
Creates a new [name].
See the base [page:Loader] class for common properties.
See the base [page:Loader] class for common methods.
		[page:String url] — A string containing the path/URL of the .tga file. 
		[page:Function onLoad] — (optional) A function to be called after loading is successfully completed. The function receives loaded [page:DataTexture] as an argument.
		[page:Function onProgress] — (optional) A function to be called while the loading is in progress. The argument will be the XMLHttpRequest instance, which contains .[page:Integer total] and .[page:Integer loaded] bytes.
		[page:Function onError] — (optional) A function to be called if an error occurs during loading. The function receives the error as an argument.
		
Begin loading from url and pass the loaded [page:DataTexture texture] to onLoad. The [page:DataTexture texture] is also directly returned for immediate use (but may not be fully loaded).
[link:https://github.com/mrdoob/three.js/blob/master/examples/js/loaders/TGALoader.js examples/js/loaders/TGALoader.js]