(Just made a PR for this, mengxr was the reporter of:)

MLlib has sample data under serveral folders:
1) data/mllib
2) data/
3) mllib/data/*
Per previous discussion with Matei Zaharia, we want to put them under `data/mllib` and clean outdated files.

Author: Sean Owen <sowen@cloudera.com>

Closes #1394 from srowen/SPARK-2363 and squashes the following commits:

54313dd [Sean Owen] Move ML example data from /mllib/data/ and /data/ into /data/mllib/

1. Added synthetic datasets for `MovieLensALS`, `LinearRegression`, `BinaryClassification`.
2. Embedded instructions in the help message of those example apps.

Per discussion with Matei on the JIRA page, new example data is under `data/mllib`.

Author: Xiangrui Meng <meng@databricks.com>

Closes #833 from mengxr/mllib-sample-data and squashes the following commits:

59f0a18 [Xiangrui Meng] add sample binary classification data
3c2f92f [Xiangrui Meng] add linear regression data
050f1ca [Xiangrui Meng] add a sample dataset for MovieLensALS example

Signed-off-by: shane-huang <shengsheng.huang@intel.com>