Upgrade Mesos to 0.18.0.

Unblocks AURORA-14 from switching to an apache.org source for building
the Mesos .egg.

Testing Done:
Ran e2e test locally:

+ RETCODE=0
+ collect_result
+ [[ 0 = 0 ]]
+ echo '***'
***
+ echo 'OK (all tests passed)'
OK (all tests passed)
+ echo '***'
***
+ exit 0

Bugs closed: AURORA-322

Reviewed at https://reviews.apache.org/r/20744/
Add machine maintainer auth capability.

Bugs closed: AURORA-348

Reviewed at https://reviews.apache.org/r/20620/
AURORA-278:Review Incubator release check list

Updating LICENSE file for new JS additions.

Bugs closed: AURORA-278

Reviewed at https://reviews.apache.org/r/20782/
Removing client HTTP health checks.

Bugs closed: AURORA-361

Reviewed at https://reviews.apache.org/r/20726/
Log snapshot operations

Bugs closed: AURORA-178

Reviewed at https://reviews.apache.org/r/20469/
Stage 1 of implementing command hooks for aurora v2.

This change includes:
(1) The ability to add hard-wired hooks, by registering them in ConfigurationPlugins
  compiled into a pex;
(2) Dynamically loaded plugins, loaded from plugin files.

The dynamically loaded plugins are *not* currently active outside of tests.

The second stage of this change will activate dynamically loaded plugins, and
provide a mechanism to allow privileged users to override hooks.

Bugs closed: aurora-270

Reviewed at https://reviews.apache.org/r/20687/
AURORA-278: Review Incubator release checklist - missing license headers

Adds missing license headers for sh, js and py files as well as updates
the LICENSE for jquery in src/main/python
Revert "AURORA-29: Clean up resource files under src/resources/org/apache/"

This reverts commit ad35931b2540372b5449ec5083b6473c4a61dfd1.

Testing Done:
./pants src/test/python/apache/aurora/executor:executor-large -vxs

...

=========================================================== 15 passed in 42.15 seconds ===========================================================
Writing log files to disk in /var/folders/4d/9tz0cd5n2n7947xs21gspsxc0000gp/T/tmpyFCRNS
src.test.python.apache.aurora.executor.executor_builds                          .....   SUCCESS
src.test.python.apache.aurora.executor.gc_executor                              .....   SUCCESS
src.test.python.apache.aurora.executor.thermos_executor                         .....   SUCCESS

Bugs closed: AURORA-14

Reviewed at https://reviews.apache.org/r/19958/
Adding unhandled error logging into AsyncModule.

Bugs closed: AURORA-366

Reviewed at https://reviews.apache.org/r/20808/
AURORA-78: automate and enforce release workflow

Adds scripts to generate the CHANGELOG from JIRA, create the
release candidate, generate the release candidate VOTE email draft,
generate the release from the release candidate and the RESULT VOTE
email draft. docs/committers.md added with process flow details.

Testing Done:
Have been running these in dry-run mode, getting to the point where I can not test the release script as it requires things to be published to the dev dist. Have some changes in release script that are pending, but wanted to get feedback on the release-candidate and docs.

Bugs closed: AURORA-78

Reviewed at https://reviews.apache.org/r/19710/
Dropping "No jobs to kill" error from killTasks.

Bugs closed: AURORA-345

Reviewed at https://reviews.apache.org/r/20732/
Upgrade to pants==23

Testing Done:
./pants src/test/python:all -v

Bugs closed: AURORA-368

Reviewed at https://reviews.apache.org/r/20867/
Fixing flaky unit test.

Reviewed at https://reviews.apache.org/r/20916/
Pull cherrypy from remote repository.

Testing Done:
mba=aurora=; PANTS_VERBOSE=1 PYTHON_VERBOSE=1 ./pants src/main/python/apache/thermos/observer/bin:thermos_observer

before:
Unsatisfiable: Cannot satisfy requirements: [PythonRequirement(cherrypy==3.2.2)]

after:
Wrote /Users/wickman/clients/aurora/dist/thermos_observer.pex

Bugs closed: AURORA-368

Reviewed at https://reviews.apache.org/r/20917/
Moving kill wait to the client (Part 1: client changes)

Bugs closed: AURORA-370

Reviewed at https://reviews.apache.org/r/20950/
Change usage comment to match actual argument

Bugs closed: AURORA-375

Reviewed at https://github.com/apache/incubator-aurora/pull/8
Set owner field correctly in getTasksStatus call

Was incorrectly setting the identity field instead of the owner field in getTasksStatus call.

Testing Done:
Tested on local laptop using ./gradlew run.
Verified logs.
Looked at client code in test_status.py to ensure we are making the backend call correctly.

Bugs closed: AURORA-373

Reviewed at https://reviews.apache.org/r/21020/
Make "--help" defer to bridged help in the bridged client executable.

Reviewed at https://reviews.apache.org/r/21023/
Adjusting default health check config values.

Bugs closed: AURORA-376

Reviewed at https://reviews.apache.org/r/21025/
AURORA-14: Add jenkins-compatible script to build mesos core egg and run executor-large tests