Create setup command.

The /ma setup <arena> command is the first step in the process of
making the setup procedure more intuitive. The command consists of
the actual command handling, as well as a multi-role inner class,
and together they constitute Setup Mode.

- Toolbox; a set of tools are provided to the user, and a handler
  for the interact event will react to the usage of these tools,
  providing the primary, interactive element of Setup Mode. The
  tools are used to set regions, warps and points.
- Text input; by typing 'exp', the user can expand a given region
  in the typical directions (up, down, out), and by typing 'show',
  the user can request red wool blocks to be displayed in place of
  region frames, warps and points.

Whilst in Setup Mode, the user cannot type any commands, because
the input is intercepted due to the Conversations API - this is
by design, and may prevent some inconsistencies.

The next step in the process will be to fully remove the commands
that Setup Mode renders obsolete. The commands include, but are
not limited to:
- set(lobby)region
- expand(lobby)region
- setwarp
- addspawn
- delspawn
- addchest
- delchest