raise for status
fairly major refactor

keyring is now optional
can be used without oauth tokens to make anonymous gists
no more history shenanigans, use -c to pass a command
better configurating exception handling
removed keyring as a dependency
syntax bugfix
version bump for pypi
readme and example .gister updates
added positional arguments for filename(s)

fixes #7
Only require argparse for python < 2.7

Fixes #8