TAJO-1078: Update contributor list.

Closes #165
TAJO-1074: Query calculates wrong progress before subquery init. (jinho)

Closes #162
TAJO-962: Column reference used in LIMIT clause incurs NPE.

Closes #164
TAJO-981: Help command (\?) in tsql takes too long time. (YeonSu Han via jaehwa)

Closes #174
TAJO-1068: Add SQL Query documentation.

Closes #155
TAJO-1077: Add Derby configuration documentation.

Closes #163