Sampling: Include macros in SQL file
Sampling: Include macros in SQL file

Jira: MADLIB-678, MADLIB-584

File sample.sql_in did not include the file containing our predefined macros.
This implied that on Greenplum, the weighted sampling aggregate was defined
without a merge function. This severely impacted performance on multi-node
Greenplum instances.

hpandeycodeit/incubator-madlib,orhankislal/incubator-madlib,hpandeycodeit/incubator-madlib,orhankislal/incubator-madlib,hpandeycodeit/incubator-madlib,orhankislal/madlib,lmatthieu/incubator-madlib,njayaram2/incubator-madlib,rvs/incubator-madlib,lmatthieu/incubator-madlib,madlib/madlib,iyerr3/incubator-madlib,iyerr3/incubator-madlib,orhankislal/madlib,orhankislal/madlib,rashmi815/incubator-madlib,cooper-sloan/incubator-madlib,rashmi815/incubator-madlib,mktal/incubator-madlib,rvs/incubator-madlib,njayaram2/madlib,apache/incubator-madlib,mktal/incubator-madlib,lmatthieu/incubator-madlib,orhankislal/incubator-madlib,rvs/incubator-madlib,mktal/incubator-madlib,rvs/incubator-madlib,njayaram2/incubator-madlib,njayaram2/incubator-madlib,njayaram2/incubator-madlib,cooper-sloan/incubator-madlib,madlib/madlib,mktal/incubator-madlib,lmatthieu/incubator-madlib,cooper-sloan/incubator-madlib,cooper-sloan/incubator-madlib,rashmi815/incubator-madlib,apache/incubator-madlib,mktal/incubator-madlib,hpandeycodeit/incubator-madlib,madlib/madlib,njayaram2/madlib,apache/incubator-madlib,orhankislal/madlib,madlib/madlib,orhankislal/incubator-madlib,iyerr3/incubator-madlib,orhankislal/incubator-madlib,njayaram2/madlib,rvs/incubator-madlib,rashmi815/incubator-madlib,njayaram2/madlib,rashmi815/incubator-madlib,lmatthieu/incubator-madlib,hpandeycodeit/incubator-madlib,njayaram2/madlib,iyerr3/incubator-madlib,njayaram2/incubator-madlib,madlib/madlib,orhankislal/madlib,cooper-sloan/incubator-madlib,apache/incubator-madlib,iyerr3/incubator-madlib,apache/incubator-madlib