6.2.0 Macro class PetaPOCO Refactoring with generic test classes and Macro test suite with 21 tests

List of sources involved in this update:

umbraco.cms\businesslogic\datatype
   PreValue.cs

umbraco.cms\businesslogic\macro
   Macro.cs

umbraco.cms\businesslogic\Packager
   Installer.cs


Umbraco.Tests\BusinessLogic

   BaseORMTest.cs
   BaseORMTest_TRAL.cs
   BaseORMTest_TRAL_MacroRepository.cs 
   cms_businesslogic_Macro_Tests.cs
   
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Short test report from VS:
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------ Test started: Assembly: Umbraco.Tests.dll ------
21 passed, 0 failed, 0 skipped, took 17.74 seconds (NUnit 2.6.1).

![01 macro tests in nunit ui](https://f.cloud.github.com/assets/2162601/1589367/58779e92-526d-11e3-8b55-6cd45e34624c.png)