Add IMapFrom interface for automatic mapping configuration

[stormaref]

Creating IMapFrom interface
now destination type can inherit from an interface named IMapFrom and they can configure mapping in the same class like this:

publicclassInheritedDestinationModel:IMapFrom<SourceModel>{publicstringType{get;set;}publicintValue{get;set;}publicvoidConfigureMapping(TypeAdapterConfigconfig){config.NewConfig<SourceModel,InheritedDestinationModel>().Map(dest =>dest.Value, _ =>DesireValues.Number);}}

and even if you don't implement the method it will automatically create a new config for desire types
ex:

publicclassDestinationModel:IMapFrom<SourceModel>{publicstringType{get;set;}}

I've added a new extension method to TypeAdapterConfig named ScanInheritedTypes like this:

TypeAdapterConfig.GlobalSettings.ScanInheritedTypes(Assembly.GetExecutingAssembly());

I've created tests for all situations and tests are passed
as soon as this pull request merged I will update wiki page

[andrerav]

Thanks @stormaref!