Fix import error

See merge request !49

[update] AdaNet integration to CNNArchLang

See merge request !48

[update] BufFix: if a layer with the name "default_value" is passed the default block is used, that is fixed

[update] added CheckAdaNetMalFormedArchitecture, logs error if there is Another Layer beside a AdaNet layer, input and output. IF an AdaNet Layer is present