Add support for line number in url fragment

With this change, urls like http://hjemli.net/git/cgit/tree/ui-tree.c#43 can
be used to jump directly to the specified line number.

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

cgit.css

@@ -212,6 +212,15 @@ table.blob td.no {
 	text-align: right;
 }
 
+table.blob td.no a {
+	color: black;
+}
+
+table.blob td.no a:hover {
+	color: black;
+	text-decoration: none;
+}
+
 table.blob td.txt {
 	white-space: pre;
 	font-family: monospace;

ui-tree.c

@@ -43,7 +43,7 @@ static void print_object(const unsigned char *sha1, char *path)
 	while(idx < size) {
 		if (buf[idx] == '\n') {
 			buf[idx] = '\0';
-			htmlf("<tr><td class='no'>%d</td><td class='txt'>",
+			htmlf("<tr><td class='no'><a name='%d'>%1$d</a></td><td class='txt'>",
 			      ++lineno);
 			html_txt(buf + start);
 			html("</td></tr>\n");