Adds LinearSVC and demonstrate_scorer.py
Merge pull request #11 from halfak/scorer_work

Add LinearSVC and demonstrate_scorer.py
Handles the case where there is no previous revision rather than throwing an error.
Fixes langauge in demo extractor.
Merge pull request #12 from halfak/scorer_work

Handles the case where there is no previous revision rather than throwing...
Add 'numpy', 'scykit-learn' and 'scipy' to requirements.txt

These are necessary to run `python demonstrate_scorer.py`.

Before installing these packages, make sure you have these installed:
* python-sklearn
* python3.4-dev
* libatlas-base-dev
* gfortran