Corrade/Utility/IntrinsicsSsse3.h file new in Git master

Intrinsics for x86 SSSE3 instructions.

Equivalent to #include <tmmintrin.h> on most compilers except for GCC 4.8, where it contains an additional workaround to make the instructions available with just the CORRADE_ENABLE_SSSE3 function attribute instead of having to specify -mssse3 for the whole compilation unit.