Bugfixes - persistent settings and VP Chips

User extension settings were not being saved properly because localStorage was being assigned to the wrong options object in options_save(). Additionally, I renamed the localStorage property we modify from "userOptions" to the more specific "salvagerOptions."

In a Goons game, I discovered that VP Chips were sometimes being added as strings, resulting in the point tracker displaying scores like "111146". Making sure we're adding integers fixed this.