Don't throw away an initial error when detecting the handshake.
Upgrade LevelDB from 1.12 to 1.14:

* Fix issues 77, 87, 182, 190, 200, and 201

* Fix bug described in https://groups.google.com/d/msg/leveldb/yL6h1mAOc20/vLU64RylIdMJ

* Fix a bug where options.max_open_files was not getting clamped properly.

* Fix link to bigtable paper in docs.

* New sstables will have the file extension .ldb. .sst files will continue to be recognized.
Fix LevelDB Windows port
Squashed 'src/ripple/rocksdb/rocksdb/' content from commit 56589ab

git-subtree-dir: src/ripple/rocksdb/rocksdb
git-subtree-split: 56589ab81f6827ff7402e31b24a6d548f29a524f
Merge commit 'b156a49cff152fd52992a4823aaeafbaf70e564e' as 'src/ripple/rocksdb/rocksdb'
Make include paths relative
Add rocksdb module
Add RocksDB NodeStore backend