renamed ‚updateSidebar‘ to ‚refreshSidebarObject3D‘

- a command-name can now be set by providing an additional attribute in
the history.execute() function. This name is then displayed as the
description in Sidebar.History .

- allows us to give every command a unique description
- especially useful for CmdMultiCmds

- Resulting issues: #29, #30
- Player behaviour where the player stops when a command is executed,
undone or redone removed.

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