Make process exit codes consistent with whether an error was encountered or not

[StoneSteps]

Historically, webalizer or webalizer.exe reported exit code 0 (zero) if no errors were encountered and a non-zero value if either errors were reported or if there were no valid records found in log file. The latter causes various issues in automation scripts that report non-zero exit codes as errors and may trigger various unnecessary error-reporting processes, such as erroneous mail, etc.

Make exit codes consistent with the error conditions - if the requested command was successful, regardless whether any actual work was done or not (as long as work wasn't done as a result of an error), the exit code should be a zero.

[StoneSteps]

Changed the exit code from a failure (1) to a success (0) when no valid log records were found in the log file. Not having site traffic for some time is not a failure and shouldn't be reported as such.