Update n°7

• Added a border when players try to enter an island
• Added an option to customize the entry border message
• Added an option to enable/disable exit border/entry border

You must delete the configuration file for the new one to be generated

Update n°6

• Added metrics (https://bstats.org/plugin/bukkit/VirtualBorder)

• VirtualBorder is now open source (https://github.com/Eole7/VirtualBorder)

• Optimized barrier

• The push_distance option has been removed because it was useless