xhc-hb04.cc: fix compile warnings

remove unused vars and label
xhc-hb04.cc: fail if MAX_WAIT exceeded

also:
  print waiting messages before exiting
  if not simulating, do hal_setup(),hal_ready() only after usb connect
  add modname to main() printf's
xhc-hb04 (usb wireless mpg) sim configs

Use Frederick Rible's xhc-hb04 component to make simulator
configs for two known button layouts.

A new halfile (xhc-hb04.tcl) and component (xhc_hb04_util.comp)
make it possible to add the pendant with minor edits to a
user ini file since no glue-logic hal components are involved.
It is assumed/required that a thread named servo-thread exists.

Ini file entries:
 [XHC_HB04_BUTTONS]name=pin define button connections for the buttons
                            defined in the layout cfg file

 [XHC_HB04_CONFIG]layout=2        (required: 1|2  2 is most common)
 [XHC_HB04_CONFIG]coords= x y z a (optional, default =  x y z a)
 [XHC_HB04_CONFIG]coefs=  1 1 1 1 (optional filter coefs,
                                   not usually required)
 [XHC_HB04_CONFIG]scales= 1 1 1 1 (optional)

   layout specifies one of two button layouts.
   coords specifies the axes for the jogwheel selector.
   coefs  specifies filter coeficient terms to slow response.
   scales specifies plus/minus scale factors for each axis.

Two additional jogwheel selections provide spindle and feedrate control.