Color brush - Added linear gradient rotation

Profile editor - Updated conditions UI

src/Artemis.UI/Converters/NullToBooleanConverter.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Globalization;
+using System.Windows.Data;
+
+namespace Artemis.UI.Converters
+{
+    public class NullToBooleanConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            Parameters direction;
+            if (parameter == null)
+                direction = Parameters.Normal;
+            else
+                direction = (Parameters)Enum.Parse(typeof(Parameters), (string)parameter);
+
+            if (direction == Parameters.Normal)
+            {
+                if (value == null)
+                    return false;
+                return true;
+            }
+
+            if (value == null)
+                return true;
+            return false;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+
+        private enum Parameters
+        {
+            Normal,
+            Inverted
+        }
+    }
+}