Several small-to-medium size changes in this commit:

1) yale_mvpa_classify.m now returns results structure.
2) Fixed adding of 'helpers' directory to Matlab path.
3) yale_mvpa_config_classifier.m now adds 'cheat' options for testing classifiers. Current support is only temporary and not robust at all. Grep for 'cheat' in m-files to get full status.
4) yale_mvpa_config_general.m now adds 'results_verbose' option for spitting out classification results to Matlab command window (or not).
5) yale_mvpa_display_process_results.m adds support for multiple iterations and the 'results_verbose' option.
6) Several changes to yale_mvpa_doclassification.m; think they're all working, but worth double-checking:
   6a: Added back support for numeric value of yale_mvpa_config.classifier.kfold, so now it can be that or 'runs'. The value 'subs' is still not supported, and empty values (indicating separate training/test sets) still have only limited support and are not super-robust.
   6b: Added back support for multiple iterations (yale_mvpa_config.classifier.nits).
   6c: Improved progress indicator text that does not print out a million lines; rather, it prints a single line that updates.
   6d: Added in placeholder text for yale_mvpa_config.classifier.cheat option to be added in robustly later.
7) Changes to yale_mvpa_doclassification_divide_traintest.m:
   7a: Added back support for numeric value of yale_mvpa_config.classifier.kfold
   7b: Added temporary, crappy, and quite possibly incorrect support for yale_mvpa_config.classifier.cheat option.
8) Very minor change in yale_mvpa_results_auc.m, just renamed indexing variable from j to i.