Improvement: Vulnerabilities / Resistances / Immunities should be icons, not words

[magroader]

From comment on #443

I have a stash where I tried to get this working. It didn't work!

I tried to get the Vulnerabilities to show as icons using gooey.dynamic_list and was having a lot of trouble for some reason. Issues seemed to be:

• gooey.horizontal_dynamic_list doesn't actually return gooey.dynamic_list, which makes it useless
• The individual items were not visible. The original template item WAS visible and never went away (like it seems to do in other lists). This was despite the items seeming to be created (which I determined by stepping through gooey and putting in some prints) and my move flipbooks seeming to work (they spouted errors when I did things wrong, and were silently golden when things were right).
• When switching pokemon, gooey would complain that nodes were deleted. I suspect this is because gooey keeps a reference to nodes around, so those references would need to be cleared out on switching pokemon or else we would need to not delete the nodes