message: Reduce redundancy in AppVeyor matrix
diff: BOND_CONFIG: Debug
  - BOND_BUILD: "C# .NET Core"
  BOND_CONFIG: Debug
  + # C++ Core build and tests
  - BOND_BUILD: C++
  BOND_VS: "Visual Studio 14 2015"
  BOND_VS_NUM: 14
  BOND_ARCH: 64
  BOND_BOOST: 60
  - BOND_CMAKE_FLAGS: "-DBOND_CORE_ONLY=TRUE"
  + BOND_CMAKE_FLAGS: "-DBOND_ENABLE_COMM=FALSE;-DBOND_ENABLE_GRPC=FALSE"
  - BOND_BUILD: Doc
  - BOND_BUILD: C#
  BOND_OUTPUT: Fields
  BOND_CONFIG: Fields
  - # quick build sanity check
  - - BOND_BUILD: C++
  - BOND_VS: "Visual Studio 14 2015"
  - BOND_VS_NUM: 14
  - BOND_ARCH: 64
  - BOND_BOOST: 60
  - BOND_CMAKE_FLAGS: "-DBOND_SKIP_CORE_TESTS=TRUE;-DBOND_SKIP_GBC_TESTS=TRUE"
  - BOND_BUILD: Python
  BOND_VS: "Visual Studio 14 2015"
  BOND_VS_NUM: 14
  BOND_ARCH: 64
  BOND_BOOST: 63
  BOND_CMAKE_FLAGS: "-DBOND_ENABLE_COMM=FALSE;-DBOND_ENABLE_GRPC=FALSE"
  - # Core build and tests
  - - BOND_BUILD: C++
  - BOND_VS: "Visual Studio 14 2015"
  - BOND_VS_NUM: 14
  - BOND_ARCH: 64
  - BOND_BOOST: 60
  - BOND_CMAKE_FLAGS: "-DBOND_ENABLE_COMM=FALSE;-DBOND_ENABLE_GRPC=FALSE"
  - # Comm build and tests
  + # C++ Comm build and tests
  - BOND_BUILD: C++
  BOND_VS: "Visual Studio 14 2015"
  BOND_VS_NUM: 14
  BOND_ARCH: 64
  BOND_BOOST: 63
  BOND_CMAKE_FLAGS: "-DBOND_ENABLE_GRPC=FALSE;-DBOND_SKIP_CORE_TESTS=TRUE;-DBOND_SKIP_GBC_TESTS=TRUE"
  - # gRPC++ build and tests
  + # C++ gRPC build and tests
  - BOND_BUILD: C++
  BOND_VS: "Visual Studio 14 2015"
  BOND_VS_NUM: 14
  - BOND_BUILD: C#
  BOND_OUTPUT: Properties
  BOND_CONFIG: Debug
  - # Core build and tests (Visual C++ 2013)
  + # C++ Core build and tests (Visual C++ 2013)
  - BOND_BUILD: C++
  BOND_VS: "Visual Studio 12 2013"
  BOND_VS_NUM: 12
  BOND_ARCH: 32
  BOND_BOOST: 58
  BOND_CMAKE_FLAGS: "-DBOND_ENABLE_COMM=FALSE;-DBOND_ENABLE_GRPC=FALSE;-DBOND_SKIP_GBC_TESTS=TRUE"
  - # Comm build and tests (Visual C++ 2013)
  + # C++ Comm build and tests (Visual C++ 2013)
  - BOND_BUILD: C++
  BOND_VS: "Visual Studio 12 2013"
  BOND_VS_NUM: 12
  