Goran Brkić

Fix issue with cmake on windows system outside msbuild environment

1

Fixing https://github.com/nlohmann/crow/issues/33

Travis builds fail due to CMake version

3

[CMakeLists](https://github.com/nlohmann/crow/blob/master/CMakeLists.txt) file declares that minimum supported is **3.8**, but on Travis it seems that **osx_image: xcode8** has version **3.6.1**. On develop branch xcode8 is not part of the test build,...