Squashed 'src/snappy/snappy/' content from commit 1ff9be9

git-subtree-dir: src/snappy/snappy
git-subtree-split: 1ff9be9b8fafc8528ca9e055646f5932aa5db9c4
Merge commit 'd5ebc515e4b382741ec2f6823610e26e5d811787' as 'src/snappy/snappy'
Add .gitattributes for src/snappy
Add snappy compression integration
[WIP] Enable leveldb snappy. Configure from config.cfg