Many bug fixes

Hey there ! Skript-1.8 now implements all changes from Skript v2.6.2 !
The full changelog is available here : https://github.com/SkriptLang/Skript/releases/tag/2.6.2

Changes done on this fork :

• Fixed the title effect (#42)
• Fixed more issues with item comparisons
• Improved docs about addons

Enjoy ! If you encounter any issues due to this particular fork, please report them on GitHub.