Automatic long-distance walking via assisted auto-forward.

Allows automatic long-distance travel using auto-forward
and auto-jump or stairs by preparing special roadways.  This
allows players to build travel networks that can be traversed
unattended without the use of fast-travel mods.

When using auto-forard and pointed close enough to one of
the four cardinal directions, players will "snap" to traveling
exactly along that cardinal axis.

When a tunnel turn is detected (a 90 degree angle in the path
surrounded by walls) the player will automatically turn and
continue along the new direction, providing a means of traveling
more complex routes.

No dependencies.

Only works well with desktop game clients, as mobile clients
currently may lack the auto-forward feature.