Fixed database query to correctly reflect if sample arrays are empty.  Return actual document instead of truthy value. Added output file name and timestamp to save_results.:

Add conf.py entry for the number of result file lines to use for
each document in the bed and peak collections.

Instead of one result file line per document, add them in batches
to reduce the overall number of documents in the collections.
Each document now contains a `result_lines` entry, which is a list
of dictionaries, one result file line per list element.

Added valid_sample checking in database.  Fixed db_save_results to use sample ids.  Adjusted memory request usage for spp & db_save.

Added db_save_results yaml job, and script.  Updated workflow information tracking to create correct meta data files for saving information to the database.  Conf adjusted to support yaml files, and arbitrary result files.  workflow_job can now return a dictionary of all arguments used.

Added bed & peak file saving functionality to the database class.  Updated testing script to use unittests.  Updated experiment_from_samples script to only print out unique values.  Added list of current tools to conf.

Added genome validation.  Added module loading with minor validation.  Added required file detection in modules.

Added download script.  Updated job yaml.  Updated module yaml.  Add executable loading to workflow code.  Updated database validation for new inputs.