Merge git://repo.or.cz/git-gui into pt/git-gui

* git://repo.or.cz/git-gui:
  git-gui: fix size and position of window panes on startup
  git-gui: mc cannot be used before msgcat has been loaded
  git-gui: use textconv filter for diff and blame
  git-gui: Avoid using the <<Copy>> binding as a menu accelerator on win32
  git-gui: fix shortcut creation on cygwin
  git-gui: fix PATH environment for mingw development environment
  git-gui: fix usage of _gitworktree when creating shortcut for windows
  git-gui: fix "Explore Working Copy" for Windows again
  git-gui: fix usage of themed widgets variable
  git-gui: Handle failure of core.worktree to identify the working directory.
  git-gui: check whether systems nice command works or disable it

diff --cc git-gui/git-gui.sh
Simple merge

diff --cc git-gui/lib/blame.tcl
Simple merge

diff --cc git-gui/lib/choose_repository.tcl
Simple merge

diff --cc git-gui/lib/diff.tcl
Simple merge

diff --cc git-gui/lib/option.tcl
Simple merge

diff --cc git-gui/lib/shortcut.tcl
Simple merge

diff --cc git-gui/lib/status_bar.tcl
Simple merge

diff --cc git-gui/lib/win32.tcl
Simple merge

diff --cc git-gui/windows/git-gui.sh
Simple merge