pile of feather 0.4.0

• Complete syntax and file structure refactor, the module now consists of 3 files: nn.py (create, use and train neural nets), data_loader.py (for loading and converting data) and engine.py (the hidden core neural network engine wich is still < 100 lines of code).
• The new syntax makes it easier and more intuitive to create and load neural networks:
  model = nn.create(*name, *layers)
  model = nn.load(*name)
• The new file structure will also make it easier to update the module introducing new training architectures in the future