TAJO-1252: PathValidator should allow hdfs paths which contain IP addresses. (jihoon)
TAJO-1221: HA TajoClient should not connect TajoMaster at the first. (jaehwa)

Closes #286
TAJO-1254: Fix getProgress race conditions in Query. (jinho)

Closes #304
TAJO-324: Rename the prefix 'QueryUnit' to Task.

Closes #306