Add support for refs view

This enables the new urls $repo/refs, $repo/refs/heads and $repo/refs/tags,
which can be used to print _all_ branches and/or tags.

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

cgit.h

@@ -28,6 +28,7 @@
 #define CMD_BLOB     5
 #define CMD_SNAPSHOT 6
 #define CMD_TAG      7
+#define CMD_REFS     8
 
 /*
  * Dateformats used on misc. pages
@@ -260,6 +261,7 @@ extern void cgit_print_log(const char *tip, int ofs, int cnt, char *grep, char *
 extern void cgit_print_blob(struct cacheitem *item, const char *hex, char *path);
 extern void cgit_print_tree(const char *rev, char *path);
 extern void cgit_print_commit(char *hex);
+extern void cgit_print_refs();
 extern void cgit_print_tag(char *revname);
 extern void cgit_print_diff(const char *new_hex, const char *old_hex, const char *prefix);
 extern void cgit_print_snapshot(struct cacheitem *item, const char *head,