SIMD to assist VGA rendering

[sandwichdoge]

Using SSE. Check cpuid for this feature first, then implement in memcpy.
Once it's fast enough, we may use full LFB flushing. Aim to achieve at least 60FPS on 800x600x32.

[sandwichdoge]

SSE should be selected during compile time.
-DWITH_SIMD_SSE