* Install latest CMake and Python on VS 2015 image.
* Remove libs/gil from installed Boost 1.68 to ensure GIL headers
from the release are not accidentally used
Configuration summary:
- Linux (GCC 5.4), Windows (VS2017), Mac OS (clang 4.0)
- Boost 1.68 built with variant=release
- Boost.GIL built and tested using CMake w/ CMAKE_BUILD_TYPE=Release
- Basic setup of GIL IO extension dependencies is in place,
using .deb packages or Conan.
- Build without GIL IO extension tests due to issues in CMake
configuration, not related to Azure Pipelines.
Closes#188
[skip appveyor]
[skip travis]
