Replaced wvtesthelper/meter/colour scripts with an all-new wvtestrunner.pl.

Replaced wvtesthelper/meter/colour scripts with an all-new wvtestrunner.pl.

This one is much smarter than previous versions: by default, it prints out
only the headers from "Testing blah blah:" lines and then prints just a "."
for each "! whatever  ok" line.  But, if a test does fail, it prints out
*all* the stdout/stderr that was produced by the test from the "Testing blah
blah" line all the way to the failing test.

It also auto-colours ok/FAILED lines, but only if stdout is a tty, so you
don't need to decide whether you want it coloured or not.

Finally, its output is actually compatible with itself: you can run a
top-level wvtestrunner and it'll further summarize the output of inner
wvtestrunners, because the complete output of a given testrunner is in a
single "Testing blah blah:" section.  But if a failure occurs, you'll still
get the more detailed results.

(cherry picked from commit 49efbe24c148d69873ca78c05e9c5825d50ef49d)