Version 1.31 released

This version contains some very boring yet important technical upgrades (solves GFX card problems on some machines) and traditional spelling fixes and translation improvements.

– [misc] Upgraded to the newest engine (which, among other things, has an important improvement of forcing the OS to always use the best GFX card, which solves several potential technical issues).
– [misc] Upgraded third party libraries (among other things some national characters in some languages look more clear now).
– [misc] Translation (PL) improved.
– [misc] Translation (DE) improved.

– [fix] Spellbook button color.
– [fix] Many spelling fixes in the manual.