ENH: Enable ignoring class 19 (void) and log confusion matrix to tb
This patch contains the following:
- Add a new ignore_index parameter to training module, allowing to ignore class 19 during whole process
- Change aggregation to macro for some of the metrics as suggested by Iris
- Add class name in metric name on tensorboard
- Log configuration matrix to tensorboard
Closes #25 (closed) Closes #23 (closed)