Returns the value corresponding to key in the preference file if it exists.

	// Simple Editor Script that adds one or more scripts
	// to the selected GameObjects
	class ScriptAdder extends EditorWindow {
		var numComponents = 1;
		var componentsToAdd : MonoScript[];
		@MenuItem("Examples/Script Adder")
		static function Init() {
			var window = GetWindow(ScriptAdder);
			window.Show();
		}
		function Awake() {
			numComponents = EditorPrefs.GetInt("NumberOfComponents", 1);
			componentsToAdd = new MonoScript[numComponents];
		}
		function OnDestroy() {
			EditorPrefs.SetInt("NumberOfComponents", numComponents);
		}
		function OnGUI() {
			if(GUILayout.Button("Clear all components"))
				for(var c : MonoScript in componentsToAdd)
					c = null;
			EditorGUILayout.BeginHorizontal();
				if(GUILayout.Button("-")) IncreaseDecreaseComponents(-1);
				if(GUILayout.Button("+")) IncreaseDecreaseComponents(1);
			EditorGUILayout.EndHorizontal();
			for(var i = 0; i < numComponents; i++)
				componentsToAdd[i] =
					EditorGUILayout.ObjectField("Component", componentsToAdd[i], MonoScript);
			if(GUILayout.Button("Add to selection"))
				if(Selection.activeGameObject)
					for(var go : GameObject in Selection.gameObjects)
						for(var c : MonoScript in componentsToAdd)
							go.AddComponent(c.GetClass());
		}
		function IncreaseDecreaseComponents(num : int) {
			if(numComponents + num == 0) {
				numComponents = 1;
				return;
			}
			numComponents += num ;
			var newArray : MonoScript[] = new MonoScript[numComponents];
			var count = 0;
			if(num > 0)
				for(count = 0; count < componentsToAdd.Length; count++)
					newArray[count] = componentsToAdd[count];
			else
				for(count = 0; count < newArray.Length; count++)
					newArray[count] = componentsToAdd[count];
			componentsToAdd = newArray;
		}
	}