Allow empty messages

Especially for holograms

src/main/java/de/epiceric/shopchest/config/LanguageConfiguration.java

@@ -89,6 +89,9 @@ public class LanguageConfiguration extends FileConfiguration {
                             String value = sbValue.toString();
 
                             values.put(key, value);
+                        } else if (line.split("=").length == 1) {
+                            String key = line.split("=")[0];
+                            values.put(key, "");
                         }
                     }
                 }

src/main/java/de/epiceric/shopchest/nms/Hologram.java

@@ -63,7 +63,7 @@ public class Hologram {
 
             if (i != this.text.length) {
                 text = this.text[i];
-                if (text == null) continue;
+                if (text == null || text.isEmpty()) continue;
             } else {
                 if (plugin.getShopChestConfig().enable_hologram_interaction) {
                     loc = location.clone();