Use UUIDs instead of names

src/main/kotlin/net/deliciousreya/minecraftportal/MinecraftPortalPlugin.kt

@@ -26,6 +26,7 @@ import org.bukkit.event.player.PlayerMoveEvent
 import org.bukkit.plugin.java.JavaPlugin
 import org.bukkit.potion.PotionEffectType
 import java.lang.IllegalStateException
+import java.util.*
 
 class MinecraftPortalPlugin() : JavaPlugin(), Listener
 {
@@ -76,7 +77,7 @@ class MinecraftPortalPlugin() : JavaPlugin(), Listener
                 argsList[0]
             }
             sender is Player -> {
-                sender.name
+                sender.uniqueId.toString()
             }
             else -> {
                 null
@@ -87,10 +88,11 @@ class MinecraftPortalPlugin() : JavaPlugin(), Listener
             return false
         }
         if (colorString == "show") {
-            if (sender is Player && playerString == sender.name) {
+            if (sender is Player && playerString == sender.uniqueId.toString()) {
                 sender.sendMessage("Portals you create are marked with ${portals.getColorFor(playerString).name}.")
             } else {
-                sender.sendMessage("Portals created by $playerString are marked with ${portals.getColorFor(playerString).name}.")
+                val name = server.getOfflinePlayer(UUID.fromString(playerString)).name
+                sender.sendMessage("Portals created by $name are marked with ${portals.getColorFor(playerString).name}.")
             }
             return true
         }
@@ -104,7 +106,7 @@ class MinecraftPortalPlugin() : JavaPlugin(), Listener
             return false
         }
         portals.setColorFor(playerString, color)
-        if (sender is Player && playerString == sender.name) {
+        if (sender is Player && playerString == sender.uniqueId.toString()) {
             sender.sendMessage("Your portals will now be marked with ${portals.getColorFor(playerString).name}.")
         } else {
             sender.sendMessage("Portals created by $playerString will now be marked with ${portals.getColorFor(playerString).name}")
@@ -122,7 +124,7 @@ class MinecraftPortalPlugin() : JavaPlugin(), Listener
             )
             if (newPortal != null) {
                 if (newPortal.color == Material.GLASS) {
-                    newPortal.color = portals.getColorFor(e.player.name)
+                    newPortal.color = portals.getColorFor(e.player.uniqueId.toString())
                 }
                 val replacedPortal = portals.activateAndReplacePortal(newPortal)
                 val otherPortal = portals.getOtherPortal(newPortal)