[TF2] Added convar to display high-res backpack icons in econ UI + item importer futureproofing#1767

rabscootle wants to merge 2 commits intoValveSoftware:masterValveSoftware/source-sdk-2013:masterfrom

rabscootle:tf-econui-use-hires-iconsrabscootle/source-sdk-2013:tf-econui-use-hires-iconsCopy head branch name to clipboard