Flag-count going up when clicking to place flag on cell without one, and sometimes flag placing fails

[Iwantexpresso]

Found an issue where the flagcount ocassionaly goes up when trying to place a flag down on an unflagged tile, a flag is also not placed when this happens.

[Iwantexpresso]

edint found out that this might be caused by the flag grid not being properly reset after game overs, as flags from previous games seem to be stored within the flag testing matrix