egh
#52 Add support for override the
Having a go at issue #52
Adds a command line parameter --override_currency="YOUR_CURRENCY" which is then set as the currency for the print out. It also supports --override_currency="" which is my use case, where all my entries to date simply don't have a currency and that's the way I like them.
I think this is roughly following the conventions for how you've got for new code. I tried to write up a test, but the truth is I haven't been able to successfully run the test suite on my local machine, so I'm not sure if it'll pass although I think it looks about right...
This looks good, although the tests don't seem to pass. (I've been meaning to convert to pytest but haven't found the time. So apologies for the less-nice testing framework).
