Worked on the application cache, added request cache, changed some stuff over to be interfaces, added unit tests suite (need mroe) to test all caching providers.

Conflicts:
	src/Umbraco.Core/Cache/CacheProviderBase.cs
	src/Umbraco.Core/Cache/HttpRuntimeCacheProvider.cs
	src/Umbraco.Core/Cache/NullCacheProvider.cs
	src/Umbraco.Core/Cache/StaticCacheProvider.cs

src/Umbraco.Core/Cache/HttpRequestCacheProvider.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.RegularExpressions;
+using System.Web;
+
+namespace Umbraco.Core.Cache
+{
+    /// <summary>
+    /// A cache provider that caches items in the HttpContext.Items
+    /// </summary>
+    internal class HttpRequestCacheProvider : DictionaryCacheProdiverBase
+    {
+        private readonly Func<HttpContextBase> _context;
+
+        public HttpRequestCacheProvider(HttpContext context)
+        {
+            _context = () => new HttpContextWrapper(context);
+        }
+
+        public HttpRequestCacheProvider(Func<HttpContextBase> context)
+        {
+            _context = context;
+        }
+
+        protected override DictionaryCacheWrapper DictionaryCache
+        {
+            get
+            {
+                var ctx = _context();
+                return new DictionaryCacheWrapper(
+                    ctx.Items,
+                    o => ctx.Items[o],
+                    o => ctx.Items.Remove(o));
+            }
+        }
+
+        public override T GetCacheItem<T>(string cacheKey, Func<T> getCacheItem)
+        {
+            var ctx = _context();
+            var ck = GetCacheKey(cacheKey);
+            if (ctx.Items[ck] == null)
+            {
+                ctx.Items[ck] = getCacheItem();
+            }
+            return (T)ctx.Items[ck];
+        }
+    }
+}