Adding a new SST table builder based on Cuckoo Hashing

Summary:
Cuckoo Hashing based SST table builder. Contains:
- Cuckoo Hashing logic and file storage logic.
- Unit tests for logic

Test Plan:
make cuckoo_table_builder_test
./cuckoo_table_builder_test
make check all

Reviewers: yhchiang, igor, sdong, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D19545