Fixed error related to display_format in config file for some values

[apainintheneck]

Checklist

• I have read the contributing doc.
• I have included a link to the relevant issue number.
• I have checked to ensure there aren't other open pull requests
  for the same issue.
• I have written new tests for these changes, as needed.

Basically what was happening was that using display_format: pretty or display_format: short in your config file would cause an error. The reason for this was that even though those arguments were handled correctly they were sourced from the config file after those if statements had already been skipped over.

Now _display_search_results tries to source the display_format value from the config file if the export arg is empty before displaying search results. This is a small change so I didn't include any tests. Let me know if you think they are necessary and I'd be happy to add them.

Fixes #1263.

[apainintheneck]

Actually, it looks like this clobbers the --tags flag so I'll take a longer look at it.

[apainintheneck]

Okay, I had to change it to evaluate --tags before --format. Also, there was a weird thing that showed up in the unit tests where mock_args.tags was evaluating to true so I changed that as well. The funny thing is that that test isn't even testing for tags so I'm not sure why that happened.

[wren]

Looks good! Just updated the unit test to fix the tags issue you were running into.

[micahellison]

Looks good! I just added a BDD test in case of regressions.