Add meaningful docstrings to example modules

[etiology]

Hi all,

Thanks for creating this repository. Please add descriptive docstrings explaining what your example modules are doing at the top of the modules. This will help users like myself understand just what you are demonstrating in your example files.

Currently the code style and current docstrings are not clearly communicating what you are trying to show, which will likely affect developer adoption.

Example:

"""
    This example shows how to Store and Retrieve data from tables stored 
    on the device.  Specific records can be queried directly using the 
    GetRequest class with a dict of Key criteria, or via the 
    ScanRequest class to return a list of records.
"""
# -*- coding: utf-8 -*-
import random
import time
import sys

from sds.client.clientfactory import ClientFactory
from sds.client.datumutil import datum
from sds.client.datumutil import values
from sds.client.tablescanner import scan_iter
from sds.auth.ttypes import Credential
from sds.auth.ttypes import UserType
from sds.common.constants import ADMIN_SERVICE_PATH