Fix (improve) the layout on MacOS Thermal app where user drag the Thermal app to application directory.

Tcl/Tk source: https://github.com/FabriceSalvaire/CodeReview/blob/master/ressources/gitk

• list nice features
  • search in : commit message, filename, patch
• how is painted graph ?
  • tag etc.

Right now, if you want to stage all files, you need to go into "Commit" menu or use the Ctrl-I shortcut. And there is no way to unstage all files.

Going into the menu is cumbersome, and not everyone would want to use a keyboard shortcut, so add some easy to reach buttons to do this. Probably put them right after the red "Unstaged Changes" bar and the green "Staged Changes" bar. Or, put them i