Add support of anonymous types in GetMessage

[fredericcarre]

Add the possibility to decode a message from an anonymous type.
JsonConvert.DeserializeAnonymousType method can be used.

Please look at the example below:

subscriber.Subscribe("MyComponent", args =>
{
var anonymousType = new
{
Type = string.Empty,
Status = string.Empty,
Enabled = false,
Message = string.Empty,
};
var myType = args.GetMessage(anonymousType);
if (myType != null)
{
}
});