SCHEMA-223. Adds backup methods to KijiSystemTable and SystemTable backup to MetadataTool.

Signed-off-by: Lee Sheng <lsheng@wibidata.com>
SCHEMA-125. Cleans KijiSystemTable API.

Signed-off-by: Lee Sheng <lsheng@wibidata.com>
SCHEMA-101. Separates KijiSchemaTable API from implementation.

Signed-off-by: Lee Sheng <lsheng@wibidata.com>
SCHEMA-248. Kiji.modifyTableLayout() no longer takes a table name.

- Add new Kiji.modifyTableLayout() methods that don't require a
  table name argument.
- Deprecated Kiji.modifyTableLayout() methods that require a table
  name.
- Update references to use the new methods.

Signed-off-by: Christophe Taton <taton@wibidata.com>