Redraw card background to prevent visual artefacts

[dther]

Fixes #37.

[mpereira]

Thanks for the PR @dther! I assume you have tested this on Arch Linux, and it fixes the bug?

I just tested it here on macOS and there doesn't seem to be any changes, so it looks good from my side. I have a question though: do you think it makes sense for that wborder call to be in the erase_card function instead?

[mpereira]

I'll merge this PR for now and provide a release so that folks can test it. Please let me know what you think about the above 🙂

[dther]

Thanks for merging!

I tried moving the wborder call to erase_card, but it doesn't seem to fix the issue.
My rationale for placing it in draw_front is that the artefacts seem to "follow" the card they're supposed to be on, and moving the entire stack doesn't cause any symbols to be left behind. wborder forces the card's background to be redrawn, overwriting the symbols.

Oddly enough, this seems to have fixed another visual bug I found, where the cursor seems to "uncenter" itself to the left every time it interacted with a glitched stack, but would fix itself after being moved in any way.

I will confess that I learnt ncurses literally yesterday, so I'm not familiar enough with it to know the ins and outs of how wborder works...