SSE/AVX clean up

[vhirtham]

SSE should always work! AVX is enabled automatically if it is available. To check availability have a look at this list of defines

To check if the defines work as expected even though the own computer does not support them (-march=native), one can add the following compile flags: -mavx2 -mavx512f

• [x] Remove SSE related options from CMake scripts
• [x] Add #ifdefto source files if needed
• [x] Put the fused multiply add functions in a '#ifndef`#else block (check version number for that).
• [x] Implement fused multiply add for SSE version that do not support this operation. It is just a combination of _mm_mul and _mm_add

[vhirtham]

commit dd6af47385ba30f2f9fbd5bb49ca3cba1928350d