It doesn't exactly work.  Fixed one error to find another

$ ./facedancer-skel.py
Facedancer reset
GoodFET monitor initialized
MAXUSB initialized
MAXUSB enabled
MAXUSB revision 19
MAXUSB connected device USB skel device
USB skel device received SET_ADDRESS request for address 14
USB skel device received GET_DESCRIPTOR req 1, index 0, language 0x0000, length 8
MAXUSB wrote 12 01 00 01 00 00 00 40 to endpoint 0
USB skel device received GET_DESCRIPTOR req 1, index 0, language 0x0000, length 18
MAXUSB wrote 12 01 00 01 00 00 00 40 f0 ff f0 ff 03 00 01 02 03 01 to endpoint 0
USB skel device received GET_DESCRIPTOR req 2, index 0, language 0x0000, length 9
Traceback (most recent call last):
  File "./facedancer-skel.py", line 18, in <module>
    d.run()
  File "/home/r00tkillah/src/goodfet/trunk/client/USBDevice.py", line 93, in run
    self.maxusb_app.service_irqs()
  File "/home/r00tkillah/src/goodfet/trunk/client/MAXUSBApp.py", line 231, in service_irqs
    self.connected_device.handle_request(req)
  File "/home/r00tkillah/src/goodfet/trunk/client/USBDevice.py", line 171, in handle_request
    handler(req)
  File "/home/r00tkillah/src/goodfet/trunk/client/USBDevice.py", line 231, in handle_get_descriptor
_request
    response = response(dindex)
  File "/home/r00tkillah/src/goodfet/trunk/client/USBDevice.py", line 245, in handle_get_configurat
ion_descriptor_request
    return self.configurations[num].get_descriptor()
  File "/home/r00tkillah/src/goodfet/trunk/client/USBConfiguration.py", line 29, in get_descriptor
    interface_descriptors += i.get_descriptor()
  File "/home/r00tkillah/src/goodfet/trunk/client/USBInterface.py", line 86, in get_descriptor
    self.string_index
ValueError: byte must be in range(0, 256)