Revert "Merge pull request #246 from Slowpython/master"

This reverts commit 47d9740e33f47c455bc9c3b5923dfc9629782710, reversing
changes made to ba5599aff7dc9e0954ca3ae72a8947b4f9db8d84.

Conflicts:
	src/NLog/LayoutRenderers/AssemblyNameLayoutRenderer.cs
	src/NLog/LayoutRenderers/AssemblyRetrieveMethod.cs
	tests/NLog.UnitTests/LayoutRenderers/AssemblyNameTests.cs