Implement browser tabs.

Assets/Cryville/Crtr/Browsing/UI/ResourceBrowser.cs

@@ -2,6 +2,10 @@ using UnityEngine;
 
 namespace Cryville.Crtr.Browsing.UI {
 	public abstract class ResourceBrowser : MonoBehaviour {
+		[SerializeField]
+		Sprite m_icon;
+		public Sprite Icon { get { return m_icon; } }
+
 		protected ResourceBrowserMaster Master { get; private set; }
 		protected virtual void Awake() {
 			Master = GetComponentInParent<ResourceBrowserMaster>();