add a UDF pair for simple random sampling with replacement (SRSWR)
merge datafu
add copyright headers
minor updates to SRSWR
Merge branch 'master' of github.com:linkedin/datafu
merge datafu
switch back to RandomDataImpl from commons-math-2.2
update javadoc
more javadoc
Merge pull request #74 from mengxr/master

Add a UDF pair for simple random sampling with replacement (SRSWR).