Engine

[Dumuzy]

• Add an engine to see at least 4 lines of engine evaluation after puzzle is over.
• Should be also poss. to show engine lines during the puzzle, for teaching.

[Dumuzy]

If done, this must be an open source/GPL engine and it must be possible to select a different one.
And it should be possible to make it use only n seconds. after each move made on the board.
For a first version, no engine shouold be delivered, but only the possibility to add one.
Might be just a path in a settings file.