Compatibility with Chessbase and Lichess export

[jozef2svrcek]

I noticed some interesting facts:

• Sometimes after a move there can be two separate comments. Chessbase exports comments after the move and comments before the move as two comments. E.g.: "7. a3 {In einer früheren Partie, die in der Datenbank vorhanden ist, habe ich an dieser Stelle etwas ungenau mit 7....e5 gespielt. Mein Gegner hat sich drauf vorbereitet.} {Aber ich spielte jetzt anders mit} g6"
• Chessbase uses [%EOG] for End of Game- mark. After that mark, an analysis can still follow in the main line. E.g. "50. Ke1 d2+ {[%EOG]} {Aufgegeben} 51. Kf1 d1=Q+"
• Lichess does not support comments at the beginning of a variation (based on my tests). Chessbase does. We could add a Lichess compatibility mode when exporting PGNs to convert such annotations to ones after the move. Example: "17. h3 $6 Bh5 $6 ({Hier wäre instruktiv:} 17... Bxf3 18. Nxf3 d4 $1 19. Bd3 Nxd2 20. Qxd2 dxe3 21. fxe3 $17) 18. Rc1"

The idea would be to improve the compatibility when exporting / importing from / to Lichess and Chessbase.