TAJO-1209: Pluggable line (de)serializer for DelimitedTextFile.

Closes #1209
TAJO-1204: Remove unused ServerName class. (DaeMyung Kang via jaehwa)
TAJO-1165: Needs to show error messages on query_executor.jsp. (Jihun Kang via jaehwa)
TAJO-1119: JDBC driver should support TIMESTAMP type. (jaehwa)