Bug Fix

* All: Updated README.md to make the example for refactoring more theoretical, and remove the limitation that the Package Manager Console can be used.
* All: Fixed #3: Test is freezed when hijacking the method to add an event handler. => It's infrastructure's bug. I corrected submodule Swathe. For more detail, please see its commit log.
* NuGet: Fixed #4: Multiple Prig assemblies can't be added. => Add-PrigAssembly command has always overridden PreBuildEvent. I modified it to append build events if the tag has already existed.
* NuGet: Fixed #5: Build was failed when adding Prig assembly for 3rd party library. => Added <stubbing assembly>.GetReferencedAssemblies() as Reference.