[SPARK-6536] [PySpark] Column.inSet() in Python

[davies]

>>> df[df.name.inSet("Bob", "Mike")].collect()
[Row(age=5, name=u'Bob')]
>>> df[df.age.inSet([1, 2, 3])].collect()
[Row(age=2, name=u'Alice')]

[SparkQA]

Test build #29189 has started for PR 5190 at commit 6b73a47.

• This patch merges cleanly.

[SparkQA]

Test build #29189 has finished for PR 5190 at commit 6b73a47.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class Data(weight: Double, mu: Vector, sigma: Matrix)

[AmplabJenkins]

Test PASSed.
Refer to this link for build results (access rights to CI server needed):
https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder/29189/
Test PASSed.

[rxin]

Thanks. Merging in master & branch-1.3.