Mentioning waypoint in nav upgrade's manual entry.

src/main/resources/assets/opencomputers/doc/en_US/item/navigationUpgrade.md

@@ -4,4 +4,6 @@
 
 The navigation upgrade provides location and orientation information to devices it is installed in. The coordinates the upgrade provides are relative to the center of the map that was used to craft the upgrade, and the functional range is based on the size of that map.
 
-The map inside a Navigation upgrade can be changed by re-crafting the upgrade with a new map. The old map will be returned to the player. 
+The map inside a Navigation upgrade can be changed by re-crafting the upgrade with a new map. The old map will be returned to the player.
+
+Note that this upgrade is a lot more useful when used in combination with one or more [waypoints](../block/waypoint.md).

src/main/scala/li/cil/oc/server/component/UpgradeNavigation.scala

@@ -64,7 +64,7 @@ class UpgradeNavigation(val host: EnvironmentHost with Rotatable) extends prefab
     val waypoints = Waypoints.findWaypoints(position, range).
       filter(waypoint => waypoint.getDistanceFrom(positionVec.xCoord, positionVec.yCoord, positionVec.zCoord) <= rangeSq)
     result(waypoints.map(waypoint => {
-      val delta = position.toVec3.subtract(waypoint.position.offset(waypoint.facing).toVec3)
+      val delta = positionVec.subtract(waypoint.position.offset(waypoint.facing).toVec3)
       Map(
         "position" -> Array(delta.xCoord, delta.yCoord, delta.zCoord),
         "redstone" -> waypoint.maxInput,

src/main/scala/li/cil/oc/server/machine/luac/NativeLuaArchitecture.scala

@@ -303,7 +303,7 @@ class NativeLuaArchitecture(val machine: api.machine.Machine) extends Architectu
 
     apis.foreach(_.initialize())
 
-    lua.load(classOf[Machine].getResourceAsStream(Settings.scriptPath + "machine.lua"), "=kernel", "t")
+    lua.load(classOf[Machine].getResourceAsStream(Settings.scriptPath + "machine.lua"), "=machine", "t")
     lua.newThread() // Left as the first value on the stack.
 
     true