cxx,c++: Remove c++14 references

- MSVC C++14 support obtained from: https://learn.microsoft.com/en-us/cpp/overview/visual-cpp-language-conformance?view=msvc-170
- _MSVC_VER taken from https://stackoverflow.com/a/70630/2420872

fixes: #754

README.md

@@ -64,7 +64,7 @@ effort.
 
 VTK-m Requires:
 
-  + C++11 Compiler. VTK-m has been confirmed to work with the following
+  + C++14 Compiler. VTK-m has been confirmed to work with the following
       + GCC 5.4+
       + Clang 5.0+
       + XCode 5.0+

docs/CodingConventions.md

@@ -181,7 +181,7 @@ for (auto v : vector)
     avoided in class, method, and function scopes (fully qualified
     namespace references are preferred).
 
-  + All code must be valid by the C++11 specifications. It must also
+  + All code must be valid by the C++14 specifications. It must also
     compile with Microsoft Visual Studio 2015.
 
   + New code must include regression tests that will run on the dashboards.

vtkm/internal/Configure.h.in

@@ -312,12 +312,12 @@
 #define VTKM_CUDA_VERSION_MINOR @VTKM_CUDA_VERSION_MINOR@
 #endif
 
-#if __cplusplus >= 201103L || \
-    ( defined(VTKM_MSVC) && _MSC_VER >= 1900  ) || \
+#if __cplusplus >= 201402L || \
+    ( defined(VTKM_MSVC) && _MSC_VER >= 1910 ) || \
     ( defined(VTKM_ICC)  && defined(__INTEL_CXX11_MODE__) )
-#define VTKM_HAVE_CXX_11
+#define VTKM_HAVE_CXX_14
 #else
-#error "VTK-m requires at least a C++11 compiler"
+#error "VTK-m requires at least a C++14 compiler"
 #endif
 
 //Mark if we have enabled logging.