Add a remove method to DisplayPropertyMap.

src/com/dmdirc/ChannelClient.java

@@ -103,6 +103,11 @@ public class ChannelClient implements GroupChatUser {
         return properties.get(property);
     }
 
+    @Override
+    public <T> void removeDisplayProperty(final DisplayProperty<T> property) {
+        properties.remove(property);
+    }
+
     @Override
     public DisplayPropertyMap getDisplayProperties() {
         return properties;

src/com/dmdirc/events/DisplayPropertyMap.java

@@ -58,6 +58,16 @@ public class DisplayPropertyMap {
         properties.put(property, value);
     }
 
+    /**
+     * Removes a value for the specified property.
+     *
+     * @param property The property to be removed
+     * @param <T> The type of value the property takes
+     */
+    public <T> void remove(final DisplayProperty<T> property) {
+        properties.remove(property);
+    }
+
     private static class ReadOnlyDisplayPropertyMap extends DisplayPropertyMap {
         @Override
         public <T> void put(final DisplayProperty<T> property, final T value) {

src/com/dmdirc/interfaces/GroupChatUser.java

@@ -109,6 +109,11 @@ public interface GroupChatUser {
      */
     <T> Optional<T> getDisplayProperty(final DisplayProperty<T> property);
 
+    /**
+     * Removes a property relating to how this {@link GroupChatUser} should be displayed.
+     */
+    <T> void removeDisplayProperty(final DisplayProperty<T> property);
+
     /**
      * Gets the map of all display properties for this {@link GroupChatUser}.
      *