add support for specifying multiple alternatives for sanity check paths files/dirs entries
make use of alternative sanity check paths support in toy example, enhance toy easyblock to make default sanity check paths work
remove code duplication for checking sanity check paths, refactor to stop hardcoding 'files' and 'dirs' here and there
add debug log message for paths that are not found
Merge pull request #753 from boegel/sanity_check_path_alternatives

add support for specifying multiple alternatives for sanity check paths