v2.0.20 - AAC and PlotSquared v5 support

Changelog:

• Fixed Advanced Anti Cheat / AAC support (thanks Janmm14)
• Added support for PlotSquared v5
  • Old 1.8 legacy PlotSquared is still supported, but for 1.13+ you should use PlotSquared v5
• Disallow gifting to a full inventory (thanks peacefulfarms)