Integrated ARMTableHeaderViewWithActivityIndicator into ARMBluetoothViewcontroller.
Also: Fixed issue #27: ARMBluetoothManager now makes sure that CBCentralManager is powered on before issuing the “stopScan” message.

Changes:
	- Moved ARMReuseIdentifierForTableViewHeaderWithActivityIndicator into ARMTableHeaderViewwithActivityIndicator.h so it can be globally accessible instead of only accessible from ARMNetworkViewController