shorten readme file rapidly since I always forget to update it

readme.txt

@@ -2,37 +2,10 @@
 ## ADVTRAINS ## realistic trains in Minetest!
 by orwell96 and contributors(see below)
 
-Until now are supported:
-- tracks and switches, based on angles of 30(!) degrees
-- wagons that drive on these rails and collide with nodes in the environment(they need 3x3x3 space)
--> a steam engine
--> a regular green wagon
--> a subway train (NEW!)
-- coupling /discoupling of wagons/trains
-- trains can travel through unloaded map chunks
-- head-up display for train speed and nice controls when sitting in locomotive
-- signals and bumpers
-- switches and signals controllable by mesecons
-Planned features:
-- locomotives need coal to drive (and water...)
-- more types of trains and rails(electric, diesel, maglevs...)
-- better textures
-- physics for train collisions (conservation of momentum)
-- Automatic train control (ATC) via mesecons (only available on electric/subway trains, maybe allow for more features with digilines)
-- an API, because API's are cool.
-(I will probably split trains api and actual trains into two mods, to allow for extensions to be enabled individually)
-
-Manual:
-- Use the 'Default train track' item to place tracks. In most cases it will adjust rails in the direction you need them.
-- use the trackworker tool (doctor who sonic screwdriver) to rotate tracks(right-click) and to change normal rails into switches(left-click)
-- to overcome heights you need the ramped rails, place them and you will understand.
-- right-click switches to change direction, or power them with mesecons
-- place locomotives or wagons by picking the item and placing it on a track.
-- right-click a wagon or locomotive to sit onto it.
-- inside a locomotive, use W/S to accelerate/decelerate the train. This will fail if the train can't move in the desired direction. Shift stops the train, aux1 (default E) or right-click on wagon will let you off.
-- drive two trains together and they will connect by right-clicking that green icon that appears.
-- punch the red couple icon between wagons to discouple them
+For up-to-date information, visit https://forum.minetest.net/viewtopic.php?f=9&t=14726
 
+Manual:
+If manual.pdf is not present (which is the case when you downloaded the zip file), see https://github.com/orwell96/advtrains/blob/master/manual.pdf
 
 License of code: LGPL 2.1
 License of media: CC-BY-NC-SA 3.0