ReviewMgr.rolePermissions needs non-hierarchical option

Based on input from Chris Pike @ Penn State:

On Dec 14, 2015, at 10:00 AM, Chris Pike <clp207@psu.edu> wrote:

Is there an API call get all permissions assigned to a role that doesn't look at the role hierarchy?

The ReviewManager "rolePermissions" method returns all permissions granted or inherited, but I need a method that only returns permissions directly assigned to the role.