exp_loadFiles(filenames, data_type = NULL, entity_type = "gene", ignoreUnknown = TRUE)data_type is provided.FALSE, throw an error if the data/entity type
cannot be determined for a file; otherwise, the file is ignored.data_type is specified, it is assumed that all the files
are of the given data_type and entity_type. Otherwise,
the types are autodetected based on file extensions.