Summary:
Add Java-side copy constructors for:
- Options
- DBOptions
- ColumnFamilyOptions
- WriteOptions

along with unit tests to assert the copy worked.

NOTE: Unit tests are failing in travis but it looks like a global timeout issue. These tests pass.
Closes https://github.com/facebook/rocksdb/pull/3450

Differential Revision: D6874425

Pulled By: sagar0

fbshipit-source-id: 5bde68ea5b5225e071faea2628bf8bbf10bd65ab