Change _cplusplus defines to MSVC 2013.

9 jobs for rangeiter-msvc in 3 minutes and 40 seconds
Status Job ID Name Coverage
  Test
passed #26932
VS2013
VS2013-32-bit

00:00:49

passed #26931
VS2013
VS2013-64-bit

00:00:56

passed #26930
VS2015
VS2015-32-bit

00:01:04

passed #26929
VS2015
VS2015-64-bit

00:01:19

passed #26926
Linux
clang-c++11

00:03:18

passed #26928
Linux
cppcheck

00:00:44

passed #26933
Linux
doc

00:00:24

passed #26925
Linux
gcc-c++11

00:03:39

passed #26927
Apple
macos-c++11

00:01:26