Small utility function to get vector by index.
Add Scala API for deeplearning.

- simple deeplearning call
- add an example of call usage
Unified DRF API with deep learning API.

- Scala DRF API now supports the same style of
passing arguments via anynymous function filling
algorithm object
Skeleton of deep learning tutorial.

The directory lib/resources/tutorials/deeplearning/
contains list of files which represents individual
tutorial steps.

Each file contains a text which is a pure HTML.
The list of step is referenced by the class
water.api.TutorialDeepLearning
Fix a small HTML bug - missing div