Use global config module

[kevinjfoley]

First pass at addressing #99.

[kevinjfoley]

This is just a first pass. Everything should work as is since the module is still passed on, but I would prefer to remove all function parameters that refer to command line params before merging.

@egh - what do you think so far? I went global instead of just passing the args namespace as it makes things easier. For example, to address #97 one can simply import config and then add

if config.input_date_format:
            self.args += ["--input-date-format", config.input_date_format]

to Ledger.enqueue_output.

[kevinjfoley]

Not sure if there's a better way to handle this, I was a bit surprised nose didn't handle it but I've admittedly never dealt with something like this

[egh]

Seems good enough 🤷‍♂️ I'd like to move to pytest at some point soon in any case.

[egh]

Thanks @kevinjfoley ! This seems a lot simpler. The global nature of the config doesn't bother me in a CLI app like this. In fact it would probably make it easier to allow other config mechanisms.