Remove MSVC 2013 from build and README

This is the initial commit removing MSVC 2013 support.
For now, only the automated build and README have been updated.
Code cleanup is coming in subsequent commits.

CHANGELOG.md

@@ -14,9 +14,13 @@ different versioning scheme, following the Haskell community's
 ## Unreleased ##
 
 ### C++ ###
+* MSVC 2013 support has been removed. ([Issue #851](https://github.com/microsoft/bond/issues/851))
 * Fixed MSVC warning for deprecation of `std::result_of_t` in `/std:c++17`.
   ([Issue #1007](https://github.com/microsoft/bond/issues/1007))
 
+### `gbc` and Bond compiler library ###
+* C++ codegen no longer supports MSVC 2013.
+
 ## gbc & compiler library 0.12.0.1: 2019-11-21 ##
 * IDL core version: 3.0
 * C++ version: 8.2.0

README.md

@@ -30,7 +30,7 @@ For a discussion about how Bond compares to similar frameworks see [Why Bond](ht
 ## Dependencies
 
 Bond C++ library requires some C++11 features (currently limited to those
-supported by Visual C++ 2013); a C++11 compiler is required. Additionally,
+supported by Visual C++ 2015); a C++11 compiler is required. Additionally,
 to build Bond you will need CMake (3.1+),
 [Haskell Stack](https://docs.haskellstack.org/en/stable/README/#how-to-install)
 (1.5.1+) and Boost (1.61+).
@@ -183,7 +183,7 @@ cmake .. \
 
 Install the following tools:
 
-- Visual Studio 2013, 2015, or 2017
+- Visual Studio 2015 or 2017
     - VS2017 is required to build C# Bond from source
 - .NET Core SDK ([https://www.microsoft.com/net/core](https://www.microsoft.com/net/core#windows))
     - Alternative to VS2017 for building C# Bond from source

appveyor.yml

@@ -38,16 +38,6 @@
         # overall completion time since we run multiple configurations in
         # parallel.
         matrix:
-              # C++ Core build and tests (Visual C++ 2013)
-            - BOND_BUILD: C++
-              BOND_VS_VERSION: Visual Studio 2013
-              # We need to use the Visual Studio 2015 image for the 2013 build
-              # as the C# compatibility tests need a C# 6 compiler, which is
-              # available starting with the 2015 image.
-              APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-              BOND_ARCH: 32
-              BOND_BOOST: "1.61.0"
-              BOND_CMAKE_FLAGS: "-DBOND_ENABLE_GRPC=FALSE;-DBOND_SKIP_GBC_TESTS=TRUE"
               # C++ Core build and tests
             - BOND_BUILD: C++
               APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015