Merge branch 'gb/gitweb-avatar'

* gb/gitweb-avatar: gitweb: add empty alt text to avatar img gitweb: picon avatar provider gitweb: gravatar url cache gitweb: (gr)avatar support gitweb: use git_print_authorship_rows in 'tag' view too gitweb: uniform author info for commit and commitdiff gitweb: refactor author name insertion