TAJO-75: Separate SQL.g into SQLParser.g and SQLLexer.g. (hyunsik)
TAJO-22: The package prefix should be org.apache.tajo. (DaeMyung Kang via hyunsik)
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/incubator-tajo into IMPROVE_CLI
Improved a little bit.