prepare script to investigate overlap of selected features

see lab book entry: 14.01.2013 - 17:19
fix bug in read_data_lib read_paramsearch_results

order of glomeruli was not correctly recorded for all descriptors
compare optimal parameters (determined by search) against fix values
make compare feature selection much faster and the plot nicer
sort the param selection plot according to average performance of a descriptor
really fix read paramsearch results

equal sorting of the glomeruli was not guaranteed before
rename the param selection comparison and save figure