Fix error with 'best_score' in gp.py
Fix error with 'best_score' in gp.py

Changes the 'best_score' variable to an instance variable and prevents an error.flag if the best_score never exceeds the seed_fitness (ie. the seed's original fitness score was the highest score achieved).

uvasrg/EvadeML,uvasrg/EvadeML,uvasrg/EvadeML,uvasrg/EvadeML