Identify and track "temporary" items

As a player, I would like to more easily track and remove temporary (non-inventory) items when they've expired or been used.

Examples

• The Warrior's Gift Power grants a combat edge for the duration of the power
• The High Adventure setting rule allows characters to trade bennies for one-time uses of combat edges
• The Research downtime action from the Fantasy Companion and Horror Companion gives one use of a power