Discord Game SDK integration

• Discord has deprecated it's Discord-RPC library, so project was switched into newer Discord Game SDK. 
• Discord client authentication added.
• I also planning to release game on a Discord Store at Game's Server - https://discord.gg/aDdyWuJ

Updated camera

• Camera position updated.
• Camera left/right side switching added.

FPS limit

• FPS limit option added to game settings screen.
• FPS in menu is limited to 30.