'daily requests' & country/continent prefix isocode

Sometimes it's useful to get an idea of requests/hits distribution.
Currently we only have a master counter for valid requests and failed requests.
Like "unique visitors per day", this is a simple new module to display requests group by day.
This commit has support for xterminal, html and csv output, too.

Also, i added support for country & continent prefix standard isocode for error-free joins with 3rdparty info.

best,