[SPARK-2758] UnionRDD's UnionPartition should not reference parent RDDs

Author: Reynold Xin <rxin@apache.org>

Closes #1675 from rxin/unionrdd and squashes the following commits:

941d316 [Reynold Xin] Clear RDDs for checkpointing.
c9f05f2 [Reynold Xin] [SPARK-2758] UnionRDD's UnionPartition should not reference parent RDDs
Required AM memory is "amMem", not "args.amMemory"

"ERROR yarn.Client: Required AM memory (1024) is above the max threshold (1048) of this cluster" appears if this code is not changed. obviously, 1024 is less than 1048, so change this

Author: derek ma <maji3@asiainfo-linkage.com>

Closes #1494 from maji2014/master and squashes the following commits:

b0f6640 [derek ma] Required AM memory is "amMem", not "args.amMemory"
[SPARK-2340] Resolve event logging and History Server paths properly

We resolve relative paths to the local `file:/` system for `--jars` and `--files` in spark submit (#853). We should do the same for the history server.

Author: Andrew Or <andrewor14@gmail.com>

Closes #1280 from andrewor14/hist-serv-fix and squashes the following commits:

13ff406 [Andrew Or] Merge branch 'master' of github.com:apache/spark into hist-serv-fix
b393e17 [Andrew Or] Strip trailing "/" from logging directory
622a471 [Andrew Or] Fix test in EventLoggingListenerSuite
0e20f71 [Andrew Or] Shift responsibility of resolving paths up one level
b037c0c [Andrew Or] Use resolved paths for everything in history server
c7e36ee [Andrew Or] Resolve paths for event logging too
40e3933 [Andrew Or] Resolve history server file paths
[SPARK-2737] Add retag() method for changing RDDs' ClassTags.

The Java API's use of fake ClassTags doesn't seem to cause any problems for Java users, but it can lead to issues when passing JavaRDDs' underlying RDDs to Scala code (e.g. in the MLlib Java API wrapper code). If we call collect() on a Scala RDD with an incorrect ClassTag, this causes ClassCastExceptions when we try to allocate an array of the wrong type (for example, see SPARK-2197).

There are a few possible fixes here. An API-breaking fix would be to completely remove the fake ClassTags and require Java API users to pass java.lang.Class instances to all parallelize() calls and add returnClass fields to all Function implementations. This would be extremely verbose.

Instead, this patch adds internal APIs to "repair" a Scala RDD with an incorrect ClassTag by wrapping it and overriding its ClassTag. This should be okay for cases where the Scala code that calls collect() knows what type of array should be allocated, which is the case in the MLlib wrappers.

Author: Josh Rosen <joshrosen@apache.org>

Closes #1639 from JoshRosen/SPARK-2737 and squashes the following commits:

572b4c8 [Josh Rosen] Replace newRDD[T] with mapPartitions().
469d941 [Josh Rosen] Preserve partitioner in retag().
af78816 [Josh Rosen] Allow retag() to get classTag implicitly.
d1d54e6 [Josh Rosen] [SPARK-2737] Add retag() method for changing RDDs' ClassTags.
[SPARK-2497] Included checks for module symbols too.

Author: Prashant Sharma <prashant.s@imaginea.com>

Closes #1463 from ScrapCodes/SPARK-2497/mima-exclude-all and squashes the following commits:

72077b1 [Prashant Sharma] Check separately for module symbols.
cd96192 [Prashant Sharma] SPARK-2497 Produce "member excludes" irrespective of the fact that class itself is excluded or not.
automatically set master according to `spark.master` in `spark-defaults....

automatically set master according to `spark.master` in `spark-defaults.conf`

Author: CrazyJvm <crazyjvm@gmail.com>

Closes #1644 from CrazyJvm/standalone-guide and squashes the following commits:

bb12b95 [CrazyJvm] automatically set master according to `spark.master` in `spark-defaults.conf`
Merge branch 'master' of https://github.com/apache/spark into reducer-locality
Add a unit test that checks for reducer locality