Themes can now be cloned

FluentTerminal.Models/TerminalTheme.cs

@@ -4,6 +4,19 @@ namespace FluentTerminal.Models
 {
     public class TerminalTheme
     {
+        public TerminalTheme()
+        {
+        }
+
+        public TerminalTheme(TerminalTheme other)
+        {
+            Id = other.Id;
+            Name = other.Name;
+            Author = other.Author;
+            PreInstalled = other.PreInstalled;
+            Colors = new TerminalColors(other.Colors);
+        }
+
         public Guid Id { get; set; }
         public string Name { get; set; }
         public string Author { get; set; }