Update based on players' reviews

Based on the reviews and discussions, we made the following changes:

• The game balance is tweaked - the missions 1-13 are easier and you gain more XP
• Evilopedia is now accessible from within the game
• ESC button is used for more cancel/close actions
• Hotkey tooltips are added to the in-game buttons
• The stats of towers and enemies are now displayed correctly
• Some bug fixes

Thanks for your feedback!