[SPARK-4348] [PySpark] [MLlib] rename random.py to rand.py

This PR rename random.py to rand.py to avoid the side affects of conflict with random module, but still keep the same interface as before.

```
>>> from pyspark.mllib.random import RandomRDDs
```

```
$ pydoc pyspark.mllib.random
Help on module random in pyspark.mllib:
NAME
    random - Python package for random data generation.

FILE
    /Users/davies/work/spark/python/pyspark/mllib/rand.py

CLASSES
    __builtin__.object
        pyspark.mllib.random.RandomRDDs

    class RandomRDDs(__builtin__.object)
     |  Generator methods for creating RDDs comprised of i.i.d samples from
     |  some distribution.
     |
     |  Static methods defined here:
     |
     |  normalRDD(sc, size, numPartitions=None, seed=None)
```

cc mengxr

reference link: http://xion.org.pl/2012/05/06/hacking-python-imports/

Author: Davies Liu <davies@databricks.com>

Closes #3216 from davies/random and squashes the following commits:

7ac4e8b [Davies Liu] rename random.py to rand.py

(cherry picked from commit ce0333f9a008348692bb9a200449d2d992e7825e)
Signed-off-by: Xiangrui Meng <meng@databricks.com>
[SPARK-4378][MLLIB] make ALS more Java-friendly

Add Java-friendly version of `run` and `predict`, and use bulk prediction in Java unit tests. The user guide update will come later (though we may not save many lines of code there). srowen

Author: Xiangrui Meng <meng@databricks.com>

Closes #3240 from mengxr/SPARK-4378 and squashes the following commits:

6581503 [Xiangrui Meng] check number of predictions
6c8bbd1 [Xiangrui Meng] make ALS more Java-friendly

(cherry picked from commit ca26a212fda39a15fde09dfdb2fbe69580a717f6)
Signed-off-by: Xiangrui Meng <meng@databricks.com>
[HOT FIX] make-distribution.sh fails if Yarn shuffle jar DNE

This is introduced in #3147 and is failing builds without the `-Pyarn` profile.

Author: Andrew Or <andrew@databricks.com>

Closes #3250 from andrewor14/fix-yarn-shuffle-build and squashes the following commits:

42b3d37 [Andrew Or] Do not fail fast if Yarn shuffle jar does not exist

(cherry picked from commit a0fa1ba704355a82e168aa9c16ecfed30128ade0)
Signed-off-by: Andrew Or <andrew@databricks.com>
[SPARK-4326] fix unidoc

There are two issues:

1. specifying guava 11.0.2 will cause hashInt not found in unidoc (any reason to force the version here?)
2. unidoc doesn't recognize static class defined in a base class

aarondav srowen vanzin

Author: Xiangrui Meng <meng@databricks.com>

Closes #3253 from mengxr/SPARK-4326 and squashes the following commits:

53967bf [Xiangrui Meng] fix unidoc

(cherry picked from commit 4b0c1edfdf457cde0e39083c47961184059efded)
Signed-off-by: Aaron Davidson <aaron@databricks.com>
[SPARK-4372][MLLIB] Make LR and SVM's default parameters consistent in Scala and Python

The current default regParam is 1.0 and regType is claimed to be none in Python (but actually it is l2), while regParam = 0.0 and regType is L2 in Scala. We should make the default values consistent. This PR sets the default regType to L2 and regParam to 0.01. Note that the default regParam value in LIBLINEAR (and hence scikit-learn) is 1.0. However, we use average loss instead of total loss in our formulation. Hence regParam=1.0 is definitely too heavy.

In LinearRegression, we set regParam=0.0 and regType=None, because we have separate classes for Lasso and Ridge, both of which use regParam=0.01 as the default.

davies atalwalkar

Author: Xiangrui Meng <meng@databricks.com>

Closes #3232 from mengxr/SPARK-4372 and squashes the following commits:

9979837 [Xiangrui Meng] update Ridge/Lasso to use default regParam 0.01 cast input arguments
d3ba096 [Xiangrui Meng] change 'none' back to None
1909a6e [Xiangrui Meng] change default regParam to 0.01 and regType to L2 in LR and SVM

(cherry picked from commit 32218307edc6de2b08d5f7a0db6d566081d27197)
Signed-off-by: Xiangrui Meng <meng@databricks.com>
[SPARK-4310][WebUI] Sort 'Submitted' column in Stage page by time

Author: zsxwing <zsxwing@gmail.com>

Closes #3179 from zsxwing/SPARK-4310 and squashes the following commits:

b0d29f5 [zsxwing] Sort 'Submitted' column in Stage page by time

(cherry picked from commit 825709a0b8f9b4bfb2718ecca8efc32be96c5a57)
Signed-off-by: Andrew Or <andrew@databricks.com>