Crazyhouse fix and engine toggle fix

[ksthicke]

Purpose

Fixes #257 as described in my comment there.
Also fixes an issue with the engine toggle not always working.

Pre-merge TODOs and Checks

• PGN file loads correctly
• Navigating through the move history works
• Starting the engine shows moves (test for both sides)
• Selecting a different variant loads a new board with the variant and you can make moves on the board
• In Crazyhouse the pocket pieces are shown and you can drop pieces

[QueensGambit]

Great, thanks again @ksthicke for fixing this issue.
I agree that passing movetime 60000 to the engine directly is a cleaner solution.