command line interface proposal

[deanmalmgren]

I'd like to propose the following command line interface:

# this basically just prints out the equivalent of fun --help, which should display
# all available subcommands
fun

# this is the equivalent of running the current slack_fun.py script.
fun slack mstringer

# equivalent of running the current slack dropbox_fun.py script
fun dropbox path/to/dropbox/folder

This will make it easy to have a consistent interface for other fun commands. I might further propose organization that looks something like:

./
|-- LICENSE
|-- README.md
|-- bin
|   `-- fun.py
|-- fun
|   |-- __init__.py
|   |-- dropbox.py
|   `-- slack.py
|-- requirements.txt
|-- setup.py

and that we have users store their configuration variables in a ~/.funrc.py file.