Licenses: Change WTFPL to MIT (part 1)

Part 1: All mods except default and xpanes.
Add license.txt files.
Add missing README.txt files.
Check and update copyright years for all contributors.
Improve text format and make more consistent.

mods/tnt/README.txt

@@ -1,6 +1,17 @@
 Minetest Game mod: tnt
 ======================
-by PilzAdam and ShadowNinja
+See license.txt for license information.
+
+Authors of source code
+----------------------
+PilzAdam (MIT)
+ShadowNinja (MIT)
+sofar (sofar@foo-projects.org) (MIT)
+
+Authors of media (textures)
+---------------------------
+? (MIT)
+sofar (sofar@foo-projects.org) (MIT)
 
 Introduction:
 This mod adds TNT to Minetest. TNT is a tool to help the player
@@ -15,23 +26,3 @@ There are different ways to blow up TNT:
   2. Hit a gunpowder fuze that leads to a TNT block with a torch.
   3. Activate it with mesecons (fastest way)
 Be aware of the damage radius of 7 blocks!
-
-License:
-WTFPL (see below)
-
-See also:
-http://minetest.net/
-
-         DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
-                    Version 2, December 2004
-
- Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
-
- Everyone is permitted to copy and distribute verbatim or modified
- copies of this license document, and changing it is allowed as long
- as the name is changed.
-
-            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
-   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
-
-  0. You just DO WHAT THE FUCK YOU WANT TO.