Roc-utils

- Improved coding style
- Solved potential problems

- Use "minoptsyp" as default cost-function
- Refactor package API
- Refactor code
- Added visualization for optimal points (minopt and minoptsysm)
- Added demo_basic() and demo_bootstrap()
- Renamed tutorial

- Import matplotlib lazily
- Fixlets for jupyter notebook

First functional version of roc-utils