Tell we are Metacity to avoid issues with maximized Java applications

Not the best solution, but the only way to fix the issue at the moment

See https://github.com/linuxmint/muffin/pull/11
Closes https://github.com/mate-desktop/marco/issues/133
Merge remote-tracking branch 'upstream/master'
Update keybindings files with new name
Merge remote-tracking branch 'upstream/master'
Fixed a typo in README
Make shortcuts to move windows editable by control center
Merge remote-tracking branch 'upstream/master'