allow type name to be overridden when adding mappings at index creation

Author: nordbergm

Diff for: src/Nest/DSL/CreateIndexDescriptor.cs

@@ -118,7 +118,16 @@ public CreateIndexDescriptor AddMapping<T>(Func<PutMappingDescriptor<T>, PutMapp
 			typeMappingDescriptor.ThrowIfNull("typeMappingDescriptor");
 			var d = typeMappingDescriptor(new PutMappingDescriptor<T>(this._connectionSettings));
 			var typeMapping = d._Mapping;
-			typeMapping.Name = typeof (T);
+
+			if (d._Type != null)
+			{
+				typeMapping.Name = d._Type.Name != null ? (PropertyNameMarker)d._Type.Name : d._Type.Type;
+			}
+			else
+			{
+				typeMapping.Name = typeof(T);
+			}
+
 			this._IndexSettings.Mappings.Add(typeMapping);
 
 			return this;
@@ -133,7 +142,16 @@ public CreateIndexDescriptor AddMapping<T>(RootObjectMapping rootObjectMapping,
 			typeMappingDescriptor.ThrowIfNull("typeMappingDescriptor");
 			var d = typeMappingDescriptor(new PutMappingDescriptor<T>(this._connectionSettings) { _Mapping = rootObjectMapping,});
 			var typeMapping = d._Mapping;
-			typeMapping.Name = typeof (T);
+
+			if (d._Type != null)
+			{
+				typeMapping.Name = d._Type.Name != null ? (PropertyNameMarker)d._Type.Name : d._Type.Type;
+			}
+			else
+			{
+				typeMapping.Name = typeof (T);
+			}
+
 			this._IndexSettings.Mappings.Add(typeMapping);
 
 			return this;

Diff for: src/Tests/Nest.Tests.Integration/Indices/IndicesTests.cs

@@ -259,6 +259,10 @@ public void CreateIndexUsingDescriptor()
 				.AddMapping<Person>(m => m
 					.MapFromAttributes()
 				)
+				.AddMapping<Person>(m => m
+					.MapFromAttributes()
+					.Type("override")
+				)
 				.Analysis(a=>a
 					.Analyzers(an=>an
 						.Add("standard", new StandardAnalyzer()