int on_install( object dest )

Called when the object is being installed by the player. If you return 1,
no messaging will be done by the install function. If you return 0, it will
assume something didn't work, and give a generic error. If a destination is
specified (install x on y), then it will pass that in as the dest parameter.

This is used for objects which can be attached to other objects, configuring
them or similar. Good examples would be locks on doors or signs on shops.

