Reverted the way IDocumentSerializer is used

due to Issue: #42 it's probably better at this tage to keep the
compatibility with the past regarding how the events are serialized in a
commit. We should rethink the whole usage of IDocumentSerializer.

src/NEventStore.Persistence.MongoDB/ExtensionMethods.cs

@@ -44,7 +44,7 @@ public static BsonDocument ToMongoCommit(this CommitAttempt commit, Int64 checkp
 					new BsonDocument
 					{
 						{MongoCommitFields.StreamRevision, streamRevision++},
-						{MongoCommitFields.Payload, BsonDocumentWrapper.Create(serializer.Serialize(e))}
+						{MongoCommitFields.Payload, BsonDocumentWrapper.Create(typeof(EventMessage), serializer.Serialize(e))}
 					}).ToList();
 
 			var mc = new MongoCommit
@@ -76,7 +76,7 @@ public static BsonDocument ToEmptyCommit(this CommitAttempt commit, Int64 checkp
 					new BsonDocument
 					{
 						{MongoCommitFields.StreamRevision, streamRevision++},
-						{MongoCommitFields.Payload, BsonDocumentWrapper.Create(serializer.Serialize(e))}
+						{MongoCommitFields.Payload, BsonDocumentWrapper.Create(typeof(EventMessage), serializer.Serialize(e))}
 					});
 
 			var mc = new MongoCommit
@@ -107,7 +107,7 @@ public static BsonDocument ToMongoCommit_original(this CommitAttempt commit, Int
 					new BsonDocument
 					{
 						{MongoCommitFields.StreamRevision, streamRevision++},
-						{MongoCommitFields.Payload, BsonDocumentWrapper.Create(serializer.Serialize(e))}
+						{MongoCommitFields.Payload, BsonDocumentWrapper.Create(typeof(EventMessage), serializer.Serialize(e))}
 					});
 
 			//var dictionarySerialize = new DictionaryInterfaceImplementerSerializer<Dictionary<string, object>>(DictionaryRepresentation.ArrayOfArrays);