added --config option
throw error if specified --config is not found
added docs for --config
using custom completers for handling configuration files that are specified on command line
using a memoize decorator to properly cache task_graph and task_kwargs_list if multiple config paths exist
using task_ids_completer on other TASK_ID command line arguments
refactored general purpose types into a separate module
pep8
added a test for using an alternate configuration
Merge pull request #62 from deanmalmgren/issue-62

specify alternative flo.yaml filename