sstables: add support to snappy compression
sstables: add support to snappy compression

Signed-off-by: Raphael S. Carvalho <1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@cloudius-systems.com>

linearregression/scylla,kangkot/scylla,guiquanz/scylla,gwicke/scylla,kangkot/scylla,senseb/scylla,stamhe/scylla,wildinto/scylla,bowlofstew/scylla,rentongzhang/scylla,gwicke/scylla,raphaelsc/scylla,glommer/scylla,kjniemi/scylla,eklitzke/scylla,bowlofstew/scylla,shaunstanislaus/scylla,phonkee/scylla,victorbriz/scylla,avikivity/scylla,eklitzke/scylla,stamhe/scylla,duarten/scylla,justintung/scylla,wildinto/scylla,dwdm/scylla,scylladb/scylla,glommer/scylla,senseb/scylla,justintung/scylla,guiquanz/scylla,guiquanz/scylla,bowlofstew/scylla,justintung/scylla,avikivity/scylla,rluta/scylla,shaunstanislaus/scylla,respu/scylla,rentongzhang/scylla,capturePointer/scylla,gwicke/scylla,tempbottle/scylla,kjniemi/scylla,dwdm/scylla,raphaelsc/scylla,duarten/scylla,scylladb/scylla,raphaelsc/scylla,duarten/scylla,rentongzhang/scylla,acbellini/scylla,glommer/scylla,shaunstanislaus/scylla,senseb/scylla,avikivity/scylla,capturePointer/scylla,aruanruan/scylla,capturePointer/scylla,scylladb/scylla,kangkot/scylla,rluta/scylla,phonkee/scylla,phonkee/scylla,victorbriz/scylla,respu/scylla,tempbottle/scylla,respu/scylla,asias/scylla,acbellini/scylla,victorbriz/scylla,aruanruan/scylla,eklitzke/scylla,acbellini/scylla,scylladb/scylla,asias/scylla,dwdm/scylla,linearregression/scylla,linearregression/scylla,aruanruan/scylla,kjniemi/scylla,stamhe/scylla,tempbottle/scylla,rluta/scylla,asias/scylla,wildinto/scylla