BF-Streams: Basic Concept for Scaling

[detlefarend]

Description/Motivation
A concept for scaling is needed to enable unscaling of scaled result data.

Task list

• 1. New root class bf.math.Scaler for all types of scaling including normalization
  • Methods scale, unscale, rescale
• 2. Class bf.math.Normalizer: new parent class bf.math.Scaler
• 3. Class StreamTask: new method unscale( p_inst )
  Unscales an instance by backpropagating all predecessor scalers...
• 4. Class StreamWorkflow: new method unscale( p_inst )
  Unscales an instance by backpropagating all predecessor scalers...
• 5. New class bf.streams.tasks.Scaler (parents: bf.streams.tasks.StreamTask, bf.math.Scaler)
  Scales features of a stream with static factors

Related issues
#975