curiouscat: New command to grep output of commands

curiouscat: New command to grep output of commands

curiouscat is used to filter the output of a given command.  If it matches,
the full standard out and standard error are printed.

This is useful if you have scripts run from cron that intermittently
print out "No such file or directory" because the directory structure
was changed underneath their feet, but you want to capture any other
errors.

If you pass -v, it will print stdout/stderr if there are lines that do
not match the pattern(s).