Updated Spark SQL README to include the hive-thriftserver module

Author: Reynold Xin <rxin@apache.org>

Closes #1867 from rxin/sql-readme and squashes the following commits:

42a5307 [Reynold Xin] Updated Spark SQL README to include the hive-thriftserver module

(cherry picked from commit 5b6585de6b939837d5bdc4b1a44634301949add6)
Signed-off-by: Reynold Xin <rxin@apache.org>
Turn UpdateBlockInfo into case class.

This helps us log UpdateBlockInfo properly once #1870 is merged.

Author: Reynold Xin <rxin@apache.org>

Closes #1872 from rxin/UpdateBlockInfo and squashes the following commits:

0cee1c2 [Reynold Xin] Turn UpdateBlockInfo into case class.

(cherry picked from commit 482c5afbf6f3f12ac23851300a33249b26ddff3c)
Signed-off-by: Reynold Xin <rxin@apache.org>