Fix when changing to layoutmode

Fix

• Due to the critical update of react-grid-layout, a refactoring was necessary to have basic functionality available (thanks to @alectroniq for exploring the issue!)
• Established and wired a new thunk action for changing to layout mode

Download and Install

• mac: Please, download the *.dmg File (can be seen on "assets" at the bottom here) and double click
• win: Please, download the *.exe File (can be seen on "assets" at the bottom here) and double click
• linux: Please, download the *.tar.gz File (can be seen on "assets" at the bottom here) and you know, what to do