Compability and Credits: Pre-Alpha 1.0.2 released

List of changes:

• Increased compability with different monitor types: from 4:3 to 21:9 and from 640x480 to 3840x2160, the game should look and work fine.
• Mac and Linux support enabled.
• Credits added in main menu.
• Fixed buttons sprites
• Since the work on Pre-Alpha 1.1 is already underway, there is a small leftover from it hidden on a map :)