Fixing and adding features to the scores generation script

I was using the score 'gen' script, but needed some features.

Added:

• A way of specifying how the number of scores is defined (number of subjects and probes, or manually specified);
• A way to generate different scores for dev and eval;
• Tests for the gen script.

Changed:

• The way the scores are generated (each probe against each reference model, instead of randomly).

Fixed:

• Duplicate click options (-p);
• 'positive scores' were generated with a 'negative scores' variable.