command line option '--history [seconds]'. The default is still 60
  seconds.
o Add a command line option '--interval [seconds]' to set the sample
  interval. The default sample interval without the options remains 0.2
  seconds as before.
o Add '--host [IP address or hostname]' command line option to view traces
  on a remote machine.
o Add '--port [remote port number]' command line option to specify the port
  number of the trace server to connect to.
o Add usage() function to inform user of possible optins.
o Keep track of the lowest and highest values in a plot and adjust the y
  range to be just over min and max so that all samples will fit within the
  plot, without the highest and lowest values dissapearing under the borders
  of the plot.

	modified:   common/trace/trace_view.c