iOS 8 compatibility

[Continuities]

• In the menu, the Gridland logo is covered by the “New Game” buttons.
• Sometimes, you can’t see how many potions and weapons you have (there is one empty black indicator instead of three white)
• From time to time, a monster health bar leaves a trace of little lines behind it.
• When you switch tabs in Safari, you may see the day tiles rendered over the night tiles (this problem was also present on iOS 7).