Add the return type as a column for SHOW FUNCTIONS.

Also includes some misc pattern matching cleanup.

Change-Id: I6c9ec78b094a73864b4d669afbd75a48c9bf9585
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2199
Tested-by: jenkins
Reviewed-by: Nong Li <nong@cloudera.com>