- Some kind of referer spam filtering

- Glob-style matching in --prefix, like:
	--prefix *invece.org

- Keyword trails:
	hping -> /
	hping3 -> /hping3.html
	packet MTU -> /docs.html
	...

- Month/day bidimentional map: convert it to a bicolor-map
  with trends, where every day is compared with the previous
  day of the week. For example Monday 9 will be compared with
  Monday 2, and so on. There is to find a way to avoid that
  input logs with a range more than one year will collide
  in the same Month/day, in theory only the more recent 365
  days presents in the input should be processed for this log,
  but it's not possible to know the earliest date presents
  in advance.

- Google's 'hl' parameter report.

- Keywords by first time

- Enter pages

- Best referer in every month+year. This may be done with a single
  hash table if the key is: month+year+referer, the sort it by hits,
  and get every pair of month+year one the first time (running the
  hash table form the higher hits to the lower ones).

- Best keyphrase in every month+year. See "Best referer in every month+year"
  for implementation tips.

- When the list of urls/referers/... are limited, a final
  entry "others" should sum all the non shown values.

- Countries by IP addresses? http://www.maxmind.com/app/geoip_country

- --period to limit the analysis to log entries matching the specified period.

- Processing time in seconds with decimal part, like 5,663 seconds.
  After this is implemented, it may print the lines for second speed
  if the time spent is more than 2 seconds or so.
  win32: http://mail.gnu.org/archive/html/bug-gnu-chess/2004-01/msg00020.html

- Page-specific referers

- An option to specify an external CSS name to link inside the HTML
  instead of the inline CSS.

- An option to specify the r/g/b values of the bidimentional maps

- Exclude google crawler accesses from weekday-hour map report?

- Modify parse_date() to cache the result.

- Normal "Foobar by hits" statistics should show the percentage

- Better formatting for the new reports browser/os/domain in the
  plaintext report.

- Think about hashing the time as unix-time integer instead of string in
  order to reduce processing time and memory usage.
