made POD less verbose
fixed doc reformatting typo
--circles explicitly not supported for 3d plots
y2-axis curves no longer have a thicker line by default

This was causing an issue where gnuplot would complain if a points-only
--curvestyle was plotted on the y2 axis. This is because --linewidth makes no
sense for a points-only curve
expanded test suite
'--stream --hardcopy' is now an error, not a warning
--hardcopy now handles piped output

If we tell gnuplot to plot to a file whose name starts with '|', gnuplot writes
to a a process, not to a file. This is now supported by feedgnuplot
added --hardcopy tests
streaming data now has an 'exit' command
test now uses IPC::Run directly instead of Test::Script::Run

This is required for the streaming tests I'm about to write. Test::Script::Run
doesn't know how to feed input from one process to another as the data comes in
added streaming tests
removed load test, since the functional tests all supersede it

This allows me to drop the dependency on Test::Script::Run
minor update to the timefmt doc
If using --timefmt then --xlen MUST have an integer argument

I use strftime() and strptime() to deal with xlen in the timefmt case, and those
functions only work with integers
added --timefmt tests
test harness prints out the actual command being executed
all tests now produce a higher-resolution plot
version bump