Merge branch 'kn/ref-filter-branch-list'

Merge branch 'kn/ref-filter-branch-list'

The code to list branches in "git branch" has been consolidated
with the more generic ref-filter API.

* kn/ref-filter-branch-list: (21 commits)
  ref-filter: resurrect "strip" as a synonym to "lstrip"
  branch: implement '--format' option
  branch: use ref-filter printing APIs
  branch, tag: use porcelain output
  ref-filter: allow porcelain to translate messages in the output
  ref-filter: add an 'rstrip=<N>' option to atoms which deal with refnames
  ref-filter: modify the 'lstrip=<N>' option to work with negative '<N>'
  ref-filter: Do not abruptly die when using the 'lstrip=<N>' option
  ref-filter: rename the 'strip' option to 'lstrip'
  ref-filter: make remote_ref_atom_parser() use refname_atom_parser_internal()
  ref-filter: introduce refname_atom_parser()
  ref-filter: introduce refname_atom_parser_internal()
  ref-filter: make "%(symref)" atom work with the ':short' modifier
  ref-filter: add support for %(upstream:track,nobracket)
  ref-filter: make %(upstream:track) prints "[gone]" for invalid upstreams
  ref-filter: introduce format_ref_array_item()
  ref-filter: move get_head_description() from branch.c
  ref-filter: modify "%(objectname:short)" to take length
  ref-filter: implement %(if:equals=<string>) and %(if:notequals=<string>)
  ref-filter: include reference to 'used_atom' within 'atom_value'
  ...