Layer property - Removed generic events in favor of regular ones

Layer property - Added API for easy hiding/showing properties depending on the state of another property 
Layer property - Made properties on property groups opt-out instead of opt-in, you can opt out with [LayerPropertyIgnore] attribute

src/Artemis.Core/Models/Profile/LayerProperties/Attributes/LayerPropertyIgnoreAttribute.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace Artemis.Core
+{
+    /// <summary>
+    ///     Represents an attribute that marks a layer property to be ignored
+    /// </summary>
+    public class LayerPropertyIgnoreAttribute : Attribute
+    {
+    }
+}