Add rocksdb_open_for_read_only to C API
Merge pull request #130 from donovanhide/master

Add rocksdb_open_for_read_only to C API
[Java] Fixed compile error due to the removal of ReadOptions.prefix_seek, minor improvement on DbBenchmark.java.
Fix TransactionLogIterator EOF caching

Summary:
When TransactionLogIterator comes to EOF, it calls UnmarkEOF and continues reading. However, if glibc cached the EOF status of the file, it will get EOF again, even though the new data might have been written to it.

This has been causing errors in Mac OS.

Test Plan: test passes, was failing before

Reviewers: dhruba, haobo, sdong

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18381
Support for adding TTL-ed column family

Summary:
This enables user to add a TTL column family to normal DB.

Next step should be to expand StackableDB and create StackableColumnFamily, such that users can for example add geo-spatial column families to normal DB.

Test Plan: added a test

Reviewers: dhruba, haobo, ljin

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D18201
Use new DBWithTTL API in tests
Merge branch 'master' of https://github.com/facebook/rocksdb