REFACTOR: Adding new colors to plot
REFACTOR: Replace np.nanmean/scipy.nanmean

replace two occurences of nanmean, because nanmean does not
work in older numpy/scipy versions. Replace with:

np.nansum(arr) / (arr.size - np.count_nonzero(np.isfinite(arr)))
FIX: Correct nanmean replace
REFACTOR: Add nan_mean to wrapping_util and add unittest
ENHANCEMENT: Calling HPOlib without config.cfg

Calling HPOlib is now possible in a directory without a config.cfg:

python ../../HPOlib/wrapping.py -o ../../optimizers/smac/s
	--SMAC:p=smac_2_06_01-dev/params.txt --HPOLIB:number_of_jobs=20
	--HPOLIB:function='python ../branin.py' -s 24