Merge commit 'v1.6.0' into jc/checkout-reflog-fix

Merge commit 'v1.6.0' into jc/checkout-reflog-fix

* commit 'v1.6.0': (2063 commits)
  GIT 1.6.0
  git-p4: chdir now properly sets PWD environment variable in msysGit
  Improve error output of git-rebase
  t9300: replace '!' with test_must_fail
  Git.pm: Make File::Spec and File::Temp requirement lazy
  Documentation: document the pager.* configuration setting
  git-stash: improve synopsis in help and manual page
  Makefile: building git in cygwin 1.7.0
  git-am: ignore --binary option
  bash-completion: Add non-command git help files to bash-completion
  Fix t3700 on filesystems which do not support question marks in names
  Utilise our new p4_read_pipe and p4_write_pipe wrappers
  Add p4 read_pipe and write_pipe wrappers
  bash completion: Add '--merge' long option for 'git log'
  bash completion: Add completion for 'git mergetool'
  git format-patch documentation: clarify what --cover-letter does
  bash completion: 'git apply' should use 'fix' not 'strip'
  t5304-prune: adjust file mtime based on system time rather than file mtime
  test-parse-options: use appropriate cast in length_callback
  Fix escaping of glob special characters in pathspecs
  ...

Conflicts:
	builtin-checkout.c