Update Tajo site for 0.9.0 release.
TAJO-1121: Remove the 'v2' storage package.

Closes #203
TAJO-1125: Separate logical plan and optimizer into a maven module.

Closes #210
TAJO-1125: Separate logical plan and optimizer into a maven module. (missed jar copy)
TAJO-1114: Improve ConfVars (SessionVar) to take a validator interface to check its input.
TAJO-1114: Improve ConfVars (SessionVar) to take a validator interface to check its input.
TAJO-1114: Improve ConfVars (SessionVar) to take a validator interface to check its input.
TAJO-1114: Improve ConfVars (SessionVar) to take a validator interface to check its input.
TAJO-1114: Improve ConfVars (SessionVar) to take a validator interface to check its input.
TAJO-1114: Improve ConfVars (SessionVar) to take a validator interface to check its input.
TAJO-1114: Improve ConfVars (SessionVar) to take a validator interface to check its input.