GPIOManager: ReservePin() and IsPinSet() declaration
GPIOManager: friend GPIOConsumer
GPIOManager: ReservePin and IsPinSet method declarations
GPIOManager: IsPinSet implementation
GPIOManager: add const modifier to IsPinSet method declaration
GPIOManager: remove const qualifier
GPIOManager: ReservePin signature modification; implementation
GPIOManager: Reserve pin checks pin reservation through map instead of IsPinSet
GPIOManager: defriend GPIOConsumer
GPIOConsumer: set dtor to pure virtual
GPIOConsumer: ReleasePins() method
GPIOConsumer: Add ConsumePin member
GPIOConsumer: ConsumePin() partial implementation; add const qualifer
GPIOConsumer: add pure virtual qualifier to ReleasePins member
Sensor: Add ReadValue pure virtual member
Sensor: set dtor to pure virtual
Sensor: SetInput/OutputPin member methods
HCSR04: declare inherited methods
HCSR04: echo and trigger pin private variables
HCSR04: Add Create factory method