Feature/fix #156 (#160)

* change config creator to not throw exception in there is an error......lord i hate this config creator code I need to sort it out.

* Remove method that we are not using anymore..

* throw exception and add errors to message

* train hacking and some refactoring

* bs test for code coverage

* actually return the errors in the exception

test/Ocelot.UnitTests/Errors/ErrorTests.cs

@@ -0,0 +1,18 @@
+using Ocelot.Errors;
+using Ocelot.Infrastructure.RequestData;
+using Shouldly;
+using Xunit;
+
+namespace Ocelot.UnitTests.Errors
+{
+    public class ErrorTests
+    {
+        [Fact]
+        public void should_return_message()
+        {
+            var error = new CannotAddDataError("message");
+            var result = error.ToString();
+            result.ShouldBe("message");
+        }
+    }
+}