Incorrect info about minimum supported Visual Studio version in README.md

[oleksiivorobiov]

Compilers section declares: Microsoft Visual Studio back to 12 (2013)

It's not true, I get errors:

1>x86\sse.h(3738): error C2275: 'simde__m128' : illegal use of this type as an expression
1>x86\sse.h(115) : see declaration of 'simde__m128'
1>x86\sse.h(3738): error C3861: 'SIMDE_ALIGN_ASSUME_LIKE': identifier not found

when try to compile code:

#define SIMDE_ENABLE_NATIVE_ALIASES
#include "x86/sse2.h"

int main()
{
    __m128i a = _mm_set1_epi16(5);
    __m128i b = _mm_set1_epi16(5);
    _mm_add_epi16(a, b);

    return 0;
}

According to this code https://github.com/simd-everywhere/simde/blob/master/simde/simde-align.h#L138 minimum supported version is 1900 (Visual Studio 2015 14.0), see https://en.wikipedia.org/wiki/Microsoft_Visual_C%2B%2B#Internal_version_numbering

So I suggest to change info in README.md or fix check in simde-align.h(if Visual Studio 2013 is really supported)