EC-JERASURE: rewrite region-xor function using vector operations to get ~ x1.5 speedups for erasure code and guarantee proper 64-bit/128-bit buffer alignment
Merge pull request #1056 from apeters1971/wip-jerasure-vectorop

EC-JERASURE: rewrite region-xor function using vector operations 

Reviewed-by: Loic Dachary <loic@dachary.org>