Do not attempt to refer to or make use of autowiring_USE_LIBCXX on Windows
NuSpec file should be a configuration result
Unnecessary to specify boost as a link dependency of autowiring

Boost is only required during the link step for libstdc++ when building autowiring, we should require that customers of Autowiring link to their preferred version of boost rather than trying to mandate that they use a version that we specify ourselves.  Our own internally specified version will not have the correct path, anyway, and so a specification here is counterproductive
Merge pull request #189 from leapmotion/ref-configure-nuspcec

NuSpec file should be a configuration result
Merge pull request #190 from leapmotion/bug-winlibcxx

Do not attempt to refer to or make use of autowiring_USE_LIBCXX on Windows
Merge pull request #191 from leapmotion/fix-msvc

Unnecessary to specify boost as a link dependency of autowiring