Upgrade build files to allow compiling in Visual Studio 2017#33

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IDWMaster wants to merge 2 commits intomicrosoft:masterfrom

IDWMaster:master

Commits on Aug 3, 2017

Upgrade to latest toolchain for Visual Studio 2017
IDWMaster
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Commits on Aug 4, 2017

Re-target to lower framework version to enable compatibility with older Windows versions.
IDWMaster
committed