Minor additions jfx monix implicits

Added implicit conversion from os.relpath to string for more convenient css
path dsl
Fixed some property sinks not using onchange previously
Added one sample property source binding that uses an implicit
composite cancelable

src/main/scala/nova/monadic_sfx/implicits/JavaFxMonixObservables.scala

@@ -11,6 +11,7 @@ import monix.eval.Coeval
 import monix.execution.Ack
 import monix.execution.Cancelable
 import monix.execution.Scheduler
+import monix.execution.cancelables.CompositeCancelable
 import monix.execution.cancelables.SingleAssignCancelable
 import monix.reactive.Observable
 import monix.reactive.Observer
@@ -43,11 +44,17 @@ trait JavaFXMonixObservables {
   implicit def extendedObservableList[A](
       list: ObservableList[A]
   ) = new ObservableListExt(list)
+  implicit def extendedStringObservableList(
+      list: ObservableList[String]
+  ) = new StringObservableListExt(list)
   implicit def extendedObjectPropertyObservableList[A](
       prop: ObjectProperty[ObservableList[A]]
   ) = new ObjectPropertyObservableListExt(prop)
   implicit def extendedButton(button: ButtonBase) = new ButtonBaseExt(button)
   implicit def extendedMenuItem(item: MenuItem) = new MenuItemExt(item)
+
+  // implicit val implShowForOsRelPath = Show.fromToString[os.Path]
+  implicit def osRelPath2String(path: os.RelPath): String = path.toString()
 }
 
 object JavaFXMonixObservables {
@@ -99,16 +106,18 @@ object JavaFXMonixObservables {
 
   final class PropertyExt[T, J](private val prop: Property[T, J])
       extends AnyVal {
-    def -->(op: Observer[T]) = {
-      op.onNext(prop.value)
+    def -->[J1 >: J](sub: Observer[J1]) = {
+      prop.onChange((a, b, c) => if (c != null) sub.onNext(c))
     }
 
     def ==>(op: Property[T, J]) = {
       op <== prop
     }
 
-    def <--(obs: Observable[T])(implicit s: Scheduler) = {
-      obs.doOnNextF(v => Coeval(prop.value = v)).subscribe()
+    def <--(
+        obs: Observable[_ <: T]
+    )(implicit s: Scheduler, c: CompositeCancelable): Unit = {
+      c += obs.doOnNextF(v => Coeval(prop.value = v)).subscribe()
     }
 
     def asOption = prop.map(Option(_))
@@ -211,11 +220,20 @@ object JavaFXMonixObservables {
       } else Task.unit
   }
 
+  final class StringObservableListExt(
+      private val buffer: ObservableList[String]
+  ) extends AnyVal {
+    // def ++=[T](that: Seq[T])(implicit S: Show[T]): Unit =
+    //   buffer ++= that.map(S.show)
+    // def ++=[T](that: Seq[T])(implicit C: CssPath[T]): Unit =
+    //   buffer ++= that.map(C.path)
+  }
+
   final class ReadOnlyPropertyExt[T, J](
       private val prop: ReadOnlyProperty[T, J]
   ) extends AnyVal {
-    def -->(op: Observer[T]) = {
-      op.onNext(prop.value)
+    def -->[J1 >: J](sub: Observer[J1]) = {
+      prop.onChange((a, b, c) => if (c != null) sub.onNext(c))
     }
 
     def ==>(op: Property[T, J]) = {