Added support for Xml Embedding into xml serialized messages. Closes #871
XContainerConverter for JSonMessageSerializer which allows to embed XML into the JSon serialized message
Improved test for XContainerConverter
Surrogates for BinarySerializer which allows to embed XML into the binary serialized message
Merge branch 'develop' into MessageXmlSupport

Conflicts:
	src/impl/Serializers/NServiceBus.Serializers.Json.Tests/JsonMessageSerializerTest.cs
Moved serializer tests into Core.Tests
Merge branch 'develop' into MessageXmlSupport

Conflicts:
	src/impl/Serializers/NServiceBus.Serializers.XML.Test/NServiceBus.Serializers.XML.Test.csproj
BsonSerializer works with XDocument and XElement
Fixed byte message decoders for ActiveMQ
Merge branch 'develop' into MessageXmlSupport