indexers implementation is now separated from settings/definition

so we can have multiple newznab definitions.

NzbDrone.Core/Indexers/IndexerBase.cs

@@ -0,0 +1,43 @@
+using System;
+using System.Collections.Generic;
+
+namespace NzbDrone.Core.Indexers
+{
+    public abstract class IndexerBase : IIndexer
+    {
+        public abstract string Name { get; }
+
+        public IndexerDefinition InstanceDefinition { get; set; }
+
+        public virtual IEnumerable<IndexerDefinition> DefaultDefinitions
+        {
+            get
+            {
+                yield return new IndexerDefinition
+                {
+                    Name = Name,
+                    Enable = true,
+                    Implementation = GetType().Name,
+                    Settings = string.Empty
+                };
+            }
+        }
+
+        public virtual IParseFeed Parser
+        {
+            get
+            {
+                return new BasicRssParser();
+            }
+        }
+
+        public abstract IEnumerable<string> RecentFeed { get; }
+
+        public abstract IEnumerable<string> GetEpisodeSearchUrls(string seriesTitle, int seasonNumber, int episodeNumber);
+        public abstract IEnumerable<string> GetDailyEpisodeSearchUrls(string seriesTitle, DateTime date);
+        public abstract IEnumerable<string> GetSeasonSearchUrls(string seriesTitle, int seasonNumber);
+        public abstract IEnumerable<string> GetPartialSeasonSearchUrls(string seriesTitle, int seasonNumber, int episodeWildcard);
+    }
+
+
+}