Merge beeline package into sqlline.

The org.apache.hive.sqlline package is now a merge of https://github.com/julianhyde/sqlline/commit/bdc80e8555528f9b1fd11aea0d06133e02ac6283 and org.apache.hive.beeline as of commit 3dd1295 (HIVE-2935).

BeeLine is now a sub-class of SqlLine, and most auxiliary classes in the beeline package have been removed.

Add manual.txt and maven-checkstyle-plugin.