Due to the path for the db being relative it came
to problems when importing the openingBook.nim file
in other modules (especially in ).
To change this i added a variable, that needs to point to the
root directory of the project.
Additionally i set some coding guidelines and enforced them
into the current codebase.
Integrated the engine into the playable game.
Created a menu to choose between single player and hotseat.
Added a way to choose difficulty and color in single player.