Add "unstyled" formatter func to strip control codes.

Closes #755

src/main/java/com/dmdirc/ui/messages/EventPropertyManager.java

@@ -54,6 +54,7 @@ public class EventPropertyManager {
         functions.put("lowercase", String::toLowerCase);
         functions.put("trim", String::trim);
         functions.put("bracketed", s -> Strings.isNullOrEmpty(s) ? "" : " (" + s + ')');
+        functions.put("unstyled", new StyledMessageUtils()::stripControlCodes);
     }
 
     public <S> Optional<Object> getProperty(final S object, final Class<? extends S> type, final String property) {

src/test/java/com/dmdirc/ui/messages/EventPropertyManagerTest.java

@@ -56,6 +56,7 @@ public class EventPropertyManagerTest {
         assertEquals("test 123", manager.applyFunction("TeSt 123", "lowercase"));
         assertEquals("TEST 123", manager.applyFunction("TeSt 123", "uppercase"));
         assertEquals("TeSt 123", manager.applyFunction("  TeSt 123  ", "trim"));
+        assertEquals("TeSt 123", manager.applyFunction("\2TeSt \4FFFFFF123", "unstyled"));
     }
 
     @Test