[resource_manager] Use a set when loading resource files (related to #387).
[resource_manager] Use a set when loading resource files (related to #387).

DePierre/owtf,DarKnight--/owtf,DarKnight24/owtf,owtf/owtf,DarKnight24/owtf,owtf/owtf,DePierre/owtf,sharad1126/owtf,sharad1126/owtf,owtf/owtf,DarKnight--/owtf,sharad1126/owtf,sharad1126/owtf,DarKnight24/owtf,DePierre/owtf,DePierre/owtf,owtf/owtf,DarKnight--/owtf,owtf/owtf,DarKnight24/owtf,DarKnight--/owtf