Simple chess board

## Description

A simple chess board and a chess clock without movement restrictions. Free movement as a real board.

Current features are:
• Move pieces freely, add or remove them.
• Undo/Redo last movement.
• Rotate board and/or pieces.
• Use checkers game pieces.
• Save/load positions for later use, or delete them when you don't need them anymore (swipe over them). Starting positions for chess and checkers are available.
• Use a chess clock where you can configure initial time, move time increment, increment after a number of movement, hourglass time, ...
• Set time independent for black and white if required.
• Save/load time settings for later use. Already available some common times.
• Tweet your current position.