- restructured trainer.dart
- neuron restructured
Merge branch 'master' of https://github.com/GDur/backy
- massive refactoring
  - for loops go over the length of the array what is about to change
  - shifted the error calculation from the Weight-class  to the layer class
  - made one function which multiplies the derivative of the output with the error

- added RectifierNeuron - not working yet

Signed-off-by: G A <gdur.mugen@googlemail.com>