Graal v2.31 Bug fix release

[Admins]

A new Graal version has been released which fixes several things:

- fixed bugs in the conversion of floating point to strings which bugged some scripts
- the keyboard configuration is correctly saved and loaded now
- npcs on gmaps move correctly when crossing level borders
- removed some unused buttons in the option window (F1)

Because of the scripting bug the old version (v2.3) will be disabled in a few days.

There is also a new version 3.151 for Linux, which fixes some problems with memory leaks when connecting to Graal3D.