Alien Ruin fix, various cherrypicked upstream fixes

Also adds new buildmode

code/modules/buildmode/submodes/throwing.dm

@@ -0,0 +1,29 @@
+/datum/buildmode_mode/throwing
+	key = "throw"
+	
+	var/atom/movable/throw_atom = null
+	
+/datum/buildmode_mode/throwing/Destroy()
+	throw_atom = null
+	return ..()
+
+/datum/buildmode_mode/throwing/show_help(client/c)
+	to_chat(c, "<span class='notice'>***********************************************************</span>")
+	to_chat(c, "<span class='notice'>Left Mouse Button on turf/obj/mob      = Select</span>")
+	to_chat(c, "<span class='notice'>Right Mouse Button on turf/obj/mob     = Throw</span>")
+	to_chat(c, "<span class='notice'>***********************************************************</span>")
+
+/datum/buildmode_mode/throwing/handle_click(client/c, params, obj/object)
+	var/list/pa = params2list(params)
+	var/left_click = pa.Find("left")
+	var/right_click = pa.Find("right")
+
+	if(left_click)
+		if(isturf(object))
+			return
+		throw_atom = object
+		to_chat(c, "Selected object '[throw_atom]'")
+	if(right_click)
+		if(throw_atom)
+			throw_atom.throw_at(object, 10, 1, c.mob)
+			log_admin("Build Mode: [key_name(c)] threw [throw_atom] at [object] ([AREACOORD(object)])")