Display hour numbers as 0-23 instead of 1-24

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>

gitstats

 		f.write(html_header(2, 'Hour of Day'))
 		hour_of_day = data.getActivityByHourOfDay()
 		f.write('<table><tr><th>Hour</th>')
-		for i in range(1, 25):
+		for i in range(0, 24):
 			f.write('<th>%d</th>' % i)
 		f.write('</tr>\n<tr><th>Commits</th>')
 		fp = open(path + '/hour_of_day.dat', 'w')
 
 		f.write('<tr><th>Weekday</th>')
 		for hour in range(0, 24):
-			f.write('<th>%d</th>' % (hour + 1))
+			f.write('<th>%d</th>' % (hour))
 		f.write('</tr>')
 
 		for weekday in range(0, 7):