revert -r1.45 of group.c (log was: fix window name and class to match

cwmrc(5)).  instead, fix cwmrc(5) to match the old behavior which also
happens to match the example config, of which many have based their
configs; this also nicely matches the output of xprop(1).

clean-up of variable names as a separate commit.

suggested by sthen (and something we should have done initially).

discussed with and ok oga@