[PATCH 00/16] column output (v2) and git-ls

I have fixed most of things Jonathan mentioned in the previous series, but that's not the focus. I resend column output series because it's required for git-ls patches, a more interesting command.

Column output patches:

  Move term_columns() to pager.c and save terminal width before pager
  Add display_columns() to display in column layout
  display_columns: add COL_MODE_{COLUMN,ROW} mode
  display_columns: add COL_DENSE to do unequal column layout
  Add test-column for testing column layout
  Add core.column
  parseopt: OPT_COLUMN to set struct column_layout.mode
  help: reuse display_columns() for help -a
  tag: add --column
  branch: add --column

Changes:

 - struct column_layout is gone.
 - core.column and --column takes a list of options separated by
   space/comma, so you can customize your display.

Remaining problems:

 - perhaps column.<cmd> config is better than core.column.
 - ansi_length() might misunderstand utf-8/ansi escapes
 - the heuristics to make dense layout
 - --column can also take auto/never/always
 - tests

git-ls patches:

  Add ls command
  ls: add --column
  ls: add --recursive and turn default to non-recursive mode
  ls: immitate UNIX ls output style
  ls: strip common directory prefix from output
  ls: color output

In short, git-ls is supposed to work as close as possible to UNIX ls, while still takes advantages of git-ls-files.

I split this into many patches for easier discussion. The code itself is still WIP-quality. The design may not be 100% right. Oh and I'm not sure how to do the color part right. Reading $LS_COLORS is scary and does not really fit Git.

 .gitignore                   |    2 +
 Documentation/config.txt     |   11 ++
 Documentation/git-branch.txt |    6 +
 Documentation/git-tag.txt    |    9 +-
 Makefile                     |    3 +
 builtin.h                    |    1 +
 builtin/branch.c             |   23 +++-
 builtin/ls-files.c           |  295 +++++++++++++++++++++++++++++++++++++++++-
 builtin/tag.c                |   21 +++-
 cache.h                      |    1 +
 column.c                     |  287 ++++++++++++++++++++++++++++++++++++++++
 column.h                     |   18 +++
 command-list.txt             |    1 +
 config.c                     |    4 +
 environment.c                |    1 +
 git.c                        |    1 +
 help.c                       |   52 +------
 pager.c                      |   33 +++++
 parse-options.h              |    2 +
 t/t9002-column.sh            |  108 +++++++++++++++
 test-column.c                |   57 ++++++++
 21 files changed, 879 insertions(+), 57 deletions(-)
 create mode 100644 column.c
 create mode 100644 column.h
 create mode 100755 t/t9002-column.sh
 create mode 100644 test-column.c