Compile fix for MSVC14

In Visual C++ 14, _set_output_format and _TWO_DIGIT_EXPONENT have been removed and are not needed anymore:
http://blogs.msdn.com/b/vcblog/archive/2014/06/18/crt-features-fixes-and-breaking-changes-in-visual-studio-14-ctp1.aspx
Merge pull request #20 from MarcelRaad/patch-2

Compile fix for MSVC14