Begin restructuring using Griffon

griffon-app/models/com/jdbernard/timestamper/TimeStamperMainModel.groovy

@@ -0,0 +1,12 @@
+package com.jdbernard.timestamper
+
+import groovy.beans.Bindable
+import com.jdbernard.timestamper.core.Timeline
+import com.jdbernard.timestamper.core.TimelineMarker
+import com.jdbernard.timestamper.core.TimelineProperties
+
+class TimeStamperMainModel {
+    @Bindable TimelineMarker currentMarker
+    @Bindable Timeline timeline
+    @Bindable TimelineProperties properties
+}