Added new Endpoint_ClearStatusStage() convenience function to assist with the status stages of control transfers.

Removed vague USB_IsConnected global - test USB_DeviceState or USB_HostState explicitly to gain previous functionality.

Removed USB_IsSuspended global - test USB_DeviceState against DEVICE_STATE_Suspended instead.

Fixed possible enumeration errors from spinloops which may fail to exit if the USB connection is severed before the exit condition becomes true.

Seperated out Lib components of the incomplete BluetoothHost demo application out into a seperate Lib subfolder.

Changed F_CLOCK entries in project makefiles to alias to F_CPU by default, as this is the most common case.

Copy and convert incomplete Bluetooth Host demo to the library.