Core - Create default instances for properties

UI - Added configurable width/height for brush dialogs

src/Artemis.Core/Models/Profile/LayerProperties/FloatRange.cs

@@ -9,6 +9,14 @@ namespace Artemis.Core
     {
         private readonly Random _rand;
 
+        /// <summary>
+        ///     Creates a new instance of the <see cref="FloatRange" /> class
+        /// </summary>
+        public FloatRange()
+        {
+            _rand = new Random();
+        }
+
         /// <summary>
         ///     Creates a new instance of the <see cref="FloatRange" /> class
         /// </summary>

src/Artemis.Core/Models/Profile/LayerProperties/IntRange.cs

@@ -9,6 +9,14 @@ namespace Artemis.Core
     {
         private readonly Random _rand;
 
+        /// <summary>
+        ///     Creates a new instance of the <see cref="IntRange" /> class
+        /// </summary>
+        public IntRange()
+        {
+            _rand = new Random();
+        }
+
         /// <summary>
         ///     Creates a new instance of the <see cref="IntRange" /> class
         /// </summary>

src/Artemis.Core/Models/Profile/LayerProperties/LayerProperty.cs

@@ -34,7 +34,7 @@ namespace Artemis.Core
             CurrentValue = default!;
             DefaultValue = default!;
 
-            _baseValue = default!;
+            _baseValue = typeof(T).IsValueType ? default! : Activator.CreateInstance<T>();
             _keyframes = new List<LayerPropertyKeyframe<T>>();
         }