Moved tinygettext licensing information

Moved from libraries/LICENSE.txt to LICENSE.txt. Reported by l777 on
IRC.

This was SVN commit r14956.

LICENSE.txt

@@ -62,6 +62,9 @@ in particular, let us know and we can try to clarify it.
   /source/third_party/mongoose
     MIT
 
+  /source/third_party/tinygettext
+    GPL version 2 (or later) - see license_gpl-2.0.txt
+
   /source/tools
     Various - see LICENSE.txt within that directory
 

libraries/LICENSE.txt

@@ -26,9 +26,6 @@ win32/ contains headers and precompiled static libs for Windows builds.
   source/spidermonkey
     MPL / GPL / LGPL
 
-  source/tinygettext
-    GPLv2
-
   source/valgrind
     BSD