Merge branch 'gb/gitweb-remote-heads'
* gb/gitweb-remote-heads:
git instaweb: enable remote_heads
gitweb: group remote heads by remote
gitweb: provide a routine to display (sub)sections
gitweb: refactor repository URL printing
gitweb: remotes view for a single remote
gitweb: allow action specialization in page header
gitweb: nagivation menu for tags, heads and remotes
gitweb: separate heads and remotes lists
gitweb: git_get_heads_list accepts an optional list of refs
gitweb: introduce remote_heads feature
gitweb: use fullname as hash_base in heads link