This allows users to "map" (or "link") symbols with different names so that they can be compared without having to update either the target or base objects. Symbol mappings are persisted in objdiff.json, so generators will need to ensure that they're preserved when updating. (Example: d1334bb79e)
Resolves#117
Before, this was running 2 fs::metadata
calls every frame. We don't need to do it
nearly that often, so now it only checks
once every 500ms.
This required refactoring AppConfig into
a separate AppState that holds transient
runtime state along with the loaded
AppConfig.
