Renamed cli arg from string to text as suggested by github.com/livibetter.
Half-reversion to github.com/livibetter 's addition of output cli option.
The output name is still there but the format is always forced to PNG
(with a png extension) because I think there simply isn't a better (common)
format for these file outputs.
Fixed import madness.
version bump for CLI change.
noted python 3 support in setup.py