This reverts commit 31377ce7.

Update TargetFrameworkVersions.

With Visual Studio 2015 Update 1 you should not specify -anycpu
in the runtimes section. Right now we'll have both to allow us to build
with and without Update 1, and we'll remove the old ones once we've
made the transition.

Update 1 also tries deploying implementations for some class libraries,
so I'm updating all our test and VSIX deployment class libraries to
now include implementations.