Added a ComparatorProperty and some new TODOs

Signed-off-by: palexdev <alessandro.parisi406@gmail.com>

materialfx/src/main/java/io/github/palexdev/materialfx/beans/properties/functional/ComparatorProperty.java

@@ -0,0 +1,14 @@
+package io.github.palexdev.materialfx.beans.properties.functional;
+
+import javafx.beans.property.ObjectProperty;
+import javafx.beans.property.SimpleObjectProperty;
+
+import java.util.Comparator;
+
+/**
+ * Simply an {@link ObjectProperty} that wraps a {@link Comparator}.
+ *
+ * @param <T> the type of objects that may be compared by the comparator
+ */
+public class ComparatorProperty<T> extends SimpleObjectProperty<Comparator<T>> {
+}

materialfx/src/main/java/io/github/palexdev/materialfx/beans/properties/functional/FunctionProperty.java

@@ -5,6 +5,7 @@ import javafx.beans.property.SimpleObjectProperty;
 
 import java.util.function.Function;
 
+// TODO use these properties everywhere
 /**
  * Simply an {@link ObjectProperty} that wraps a {@link Function}.
  *

materialfx/src/main/java/io/github/palexdev/materialfx/factories/InsetsFactory.java

@@ -2,6 +2,7 @@ package io.github.palexdev.materialfx.factories;
 
 import javafx.geometry.Insets;
 
+// TODO replace everywhere
 /**
  * Convenience class to build {@link Insets} objects.
  */