owner() :
Returns the address of the current owner.
renounceOwnership() :
Leaves the contract without owner. It will not be possible to call `onlyOwner` functions anymore. Can only be called by the current owner. NOTE: Renouncing ownership will leave the contract without an owner, thereby removing any functionality that is only available to the owner.
transferOwnership(address) :
Transfers ownership of the contract to a new account (`newOwner`). Can only be called by the current owner.