Removed SampleGame.makeArrays() to fix the bootstrap on ragged arrays.

The parent class's method Game.makeArrays() now gets called instead, so the values field
still gets converted, but sample_values remains a list, which prevents the index errors
Ben was experiencing. There wasn't really any good reason to make sample_values an array
so this change shouldn't break anything else.

This commit also re-does the addition of HR and DPR nicknames to Reductions.py for
easier importing of hierarchical_reduction() and dviation_preserving_reduction().