<unset> removes struct entries with inheritance again
Giving the <unset> key when inheriting ifos removes that entry from the inherited struct. For example, the arm power can be set directly with
+inherit: 'Aplus'
Laser:
Power: <unset>
ArmPower: 730e3
Laser.Power needs to be removed from the struct because that cannot be simultaneously defined with Laser.ArmPower.
A test was also added to test this behavior.