Added VS2015 as supported architecture to documentation

6 jobs for master
Status Name Job ID Coverage
  Test
passed clang-c++11 #4587
Linux

00:18:15

passed clang-c++98 #4589
Linux

00:17:03

passed gcc-c++11 #4586
Linux

00:04:33

passed gcc-c++98 #4588
Linux

00:04:12

passed macos-c++11 #4590
Apple

00:15:17

passed macos-c++98 #4591
Apple

00:08:40