IncludeShaders fails with xbuild

[flibitijibibo]

When building FNATemplate with xbuild the IncludeShaders target will fail with the all-helpful "Object reference not set to an instance of an object" error message.

My guess is this works fine with msbuild on Linux and xbuild's just broken, but if someone is really set on using xbuild, know that it's not just you.

A workaround is to simply comment out this target; it's technically not required and shaders should be in the output directory, but if you make an additional project that depends on those shaders then you'll need to copy the shaders manually.