Update README

README.txt

@@ -6,7 +6,7 @@ To build the wholeness of the Minetest project, insert this repository as
 in the Minetest Engine.
 
 The Minetest Engine can be found in:
-  https://github.com/celeron55/minetest/
+  https://github.com/minetest/minetest/
 
 Compatibility
 --------------
@@ -17,7 +17,7 @@ Additionally, when the minetest engine is tagged to be a certain version (eg.
 0.4.dev-20120326), minetest_game is tagged with the version too.
 
 When stable releases are made, minetest_game is packaged and made available in
-  https://github.com/celeron55/minetest_game/downloads
+  http://minetest.net/download.php
 and in case the repository has grown too much, it may be reset. In that sense,
 this is not a "real" git repository. (Package maintainers please note!)