Merge branch 'master' of git://repo.or.cz/git-gui

* 'master' of git://repo.or.cz/git-gui:
  git-gui: Internalize symbolic-ref HEAD reading logic
  git-gui: Expose the merge.diffstat configuration option
  git-gui: Allow users to delete remote branches
  git-gui: Allow users to rename branches through 'branch -m'
  git-gui: Disable tearoff menus on Windows, Mac OS X
  git-gui: Provide fatal error if library is unavailable
  git-gui: Enable verbose Tcl loading earlier
  git-gui: Show the git-gui library path in 'About git-gui'
  git-gui: GUI support for running 'git remote prune <name>'
  git gui 0.8.0