Feature/improved aggregate results (#1432)

* Line endings...

* Add fallback query for meta indexers

In cases where multiple indexers are configured under one
metaindexer if any of them supports IMDB search the meta
will support IMDB search as well. However the actual query will
then only be performed by those supporting IMDB search, because
others refuse it (see CanHandleQuery implementation).
- This adds support of a fallback mechanism for other indexers
- Adds first implementation of result improvement (necessary for
  fallback queries as they might produce irrelevant results)
- Some minor fixes encountered while debugging/coding

Known issue:
- Configuring nCore and IsoHunt together will render results
  from nCore unusuable. Don't know why.

src/Jackett/Models/TorznabQuery.cs

@@ -111,6 +111,48 @@ namespace Jackett.Models
             IsTest = false;
         }
 
+        public TorznabQuery CreateFallback(string search) {
+            var ret = Clone();
+            if (Categories == null || Categories.Length == 0) {
+                ret.Categories = new int[]{ TorznabCatType.Movies.ID,
+                                            TorznabCatType.MoviesForeign.ID,
+                                            TorznabCatType.MoviesOther.ID,
+                                            TorznabCatType.MoviesSD.ID,
+                                            TorznabCatType.MoviesHD.ID,
+                                            TorznabCatType.Movies3D.ID,
+                                            TorznabCatType.MoviesBluRay.ID,
+						                    TorznabCatType.MoviesDVD.ID,
+						                    TorznabCatType.MoviesWEBDL.ID,
+                };
+            }
+            ret.SearchTerm = search;
+
+            return ret;
+        }
+
+        public TorznabQuery Clone() {
+            var ret = new TorznabQuery();
+            ret.QueryType = QueryType;
+            if (Categories != null && Categories.Length > 0) {
+                ret.Categories = new int [Categories.Length];
+                Array.Copy (Categories, ret.Categories, Categories.Length);
+            }
+            ret.Extended = Extended;
+            ret.ApiKey = ApiKey;
+            ret.Limit = Limit;
+            ret.Offset = Offset;
+            ret.Season = Season;
+            ret.Episode = Episode;
+            ret.SearchTerm = SearchTerm;
+            ret.IsTest = IsTest;
+            if (QueryStringParts != null && QueryStringParts.Length > 0) {
+                ret.QueryStringParts = new string [QueryStringParts.Length];
+                Array.Copy (QueryStringParts, ret.QueryStringParts, QueryStringParts.Length);
+            }
+
+            return ret;
+        }
+
         public string GetQueryString()
         {
             return (SanitizedSearchTerm + " " + GetEpisodeSearchString()).Trim();