SPARK-3779. yarn spark.yarn.applicationMaster.waitTries config should be...

... changed to a time period

Author: Sandy Ryza <sandy@cloudera.com>

Closes #3471 from sryza/sandy-spark-3779 and squashes the following commits:

20b9887 [Sandy Ryza] Deprecate old property
42b5df7 [Sandy Ryza] Review feedback
9a959a1 [Sandy Ryza] SPARK-3779. yarn spark.yarn.applicationMaster.waitTries config should be changed to a time period
Add mesos specific configurations into doc

Author: Timothy Chen <tnachen@gmail.com>

Closes #3349 from tnachen/mesos_doc and squashes the following commits:

737ef49 [Timothy Chen] Add TOC
5ca546a [Timothy Chen] Update description around cores requested.
26283a5 [Timothy Chen] Add mesos specific configurations into doc
[SPARK-3607] ConnectionManager threads.max configs on the thread pools don't work

Hi all - cleaned up the code to get rid of the unused parameter and added some discussion of the ThreadPoolExecutor parameters to explain why we can use a single threadCount instead of providing a min/max.

Author: Ilya Ganelin <ilya.ganelin@capitalone.com>

Closes #3664 from ilganeli/SPARK-3607C and squashes the following commits:

3c05690 [Ilya Ganelin] Updated documentation and refactored code to extract shared variables
[SPARK-4887][MLlib] Fix a bad unittest in LogisticRegressionSuite

The original test doesn't make sense since if you step in, the lossSum is already NaN,
and the coefficients are diverging. That's because the step size is too large for SGD,
so it doesn't work.

The correct behavior is that you should get smaller coefficients than the one
without regularization. Comparing the values using 20000.0 relative error doesn't
make sense as well.

Author: DB Tsai <dbtsai@alpinenow.com>

Closes #3735 from dbtsai/mlortestfix and squashes the following commits:

b1a3c42 [DB Tsai] first commit