This adds an option to dragging-and-dropping which is slightly hard on
smaller screens.
Fix promotions when tapping and fix handling of subsequently tapping two pieces of your color
Cancel tap if a drag is started (tapped square will not stay red in case a drag is started)
Change url strategy back to the hashtag thing
Change version
Fix bug that would not allow a piece move if you tried to take an opponents piece.
Fix the coloring of the last move after an invalid move was played.
Upgrading deps
In window widths or heigths that are not divisible by 8, the chess board
would contain lines between the squares (since the contraints of the
chess board rows would contain non-integer constraints).
With this commit, we calculate margins manually, in order to constrict
the chess board to widths and heights that are divisible by 8.
