Weekend update 2

Trying to do one of these every weekend.

• Added help page on the homepage.
• Added support for classic terrain.png (help on using it).
• Added a button on the options screen to open the texture folder.
• Brought back debug info overlay (can be toggled with F3).
• Fix: On non-uniformly sized maps top and bottom chunks would go missing.
• Fix: With low FPS the idle function causes the cpu to spin.
• Fix: Windows Intel GPU’s showing white terrain.
• Fix: Toughen up the code in some places.

Just run the launcher and it will update it automatically!