Add a 'stats' page to each repo

This new page, which is disabled by default, can be used to print some
statistics about the number of commits per period in the repository,
where period can be either weeks, months, quarters or years.

The function can be activated globally by setting 'enable-stats=1' in
cgitrc and disabled for individual repos by setting 'repo.enable-stats=0'.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

cgit.css

@@ -456,3 +456,80 @@ div.footer {
 	font-size: 80%;
 	color: #ccc;
 }
+table.stats {
+	border: solid 1px black;
+	border-collapse: collapse;
+}
+
+table.stats th {
+	text-align: left;
+	padding: 1px 0.5em;
+	background-color: #eee;
+	border: solid 1px black;
+}
+
+table.stats td {
+	text-align: right;
+	padding: 1px 0.5em;
+	border: solid 1px black;
+}
+
+table.stats td.total {
+	font-weight: bold;
+	text-align: left;
+}
+
+table.stats td.sum {
+	color: #c00;
+	font-weight: bold;
+/*	background-color: #eee; */
+}
+
+table.stats td.left {
+	text-align: left;
+}
+
+table.vgraph {
+	border-collapse: separate;
+	border: solid 1px black;
+	height: 200px;
+}
+
+table.vgraph th {
+	background-color: #eee;
+	font-weight: bold;
+	border: solid 1px white;
+	padding: 1px 0.5em;
+}
+
+table.vgraph td {
+	vertical-align: bottom;
+	padding: 0px 10px;
+}
+
+table.vgraph div.bar {
+	background-color: #eee;
+}
+
+table.hgraph {
+	border: solid 1px black;
+	width: 800px;
+}
+
+table.hgraph th {
+	background-color: #eee;
+	font-weight: bold;
+	border: solid 1px black;
+	padding: 1px 0.5em;
+}
+
+table.hgraph td {
+	vertical-align: center;
+	padding: 2px 2px;
+}
+
+table.hgraph div.bar {
+	background-color: #eee;
+	height: 1em;
+}
+