Performance in high dimensional search-spaces

[SimonBlanke]

The issue #49 showed a slowdown of optimization algorithms in high dimensional (>1000) search-spaces. So this is aiming at improving this performance (for now) in random-search and hill-climbing. If I am successful I can adapt those changes to other optimization algorithms.

This issue does not aim to improve the performance of smbo in high-dim search-spaces. The performance of those algorithms cannot easily be improved by using some numpy arrays here and there.