Changed ObjectFactoryTests to use FluentAssertions

* ObjectFactoryTests inherits SerializationTestHelper
* The serialization test classes are moved out of the helper.
* The templating now actualy finds the assembly name through the assembly.
  This fixes a bug due to the recent test assembly merge.
Merge pull request #67 from rogernorling/objectfactorytests-refactor

Changed ObjectFactoryTests to use FluentAssertions