removing default yaw_value from DFLIMG files,

added better pitch/yaw estimator from 68 landmarks,
improving face yaw accuracy for sorting and trainers,
added sort by face-pitch

nnlib/nnlib.py

@@ -85,6 +85,7 @@ tanh = keras.layers.Activation('tanh')
 sigmoid = keras.layers.Activation('sigmoid')
 Dropout = keras.layers.Dropout
 
+Lambda = keras.layers.Lambda
 Add = keras.layers.Add
 Concatenate = keras.layers.Concatenate