Allows you to edit the contents of the tool you have in hand.
When using this command, the tool will switch into edition mode, transforming 
into a book. The commands in the book will be the tool's new commands.
Hitting "Sign" or "Done" on the book will revert it back to its normal mode, but
only if changes have been made.
Otherwise, you can use this command again to revert a tool in edition mode to 
normal mode. Trying to drop it on the ground will have the same effect.