Make markdown TOC and anchors more plaintext-friendly.

Reviewed at https://reviews.apache.org/r/18528/
Updated test to use environment variable if it exits.

Testing Done:
./build-support/jenkins/build.sh runs successfully

Bugs closed: AURORA-101

Reviewed at https://reviews.apache.org/r/18598/
Make http signaler timeout secs configurable via environment variable.

This is a band-aid for the issue described in AURORA-224. Further
improvements would be made possible by refactoring the updater
to completely remove client-side health checking (delegating to
thermos, which already supports a much richer system of delegated
health checks).

Testing Done:
./build-support/jenkins/build.sh

Bugs closed: AURORA-224

Reviewed at https://reviews.apache.org/r/18602/
Renamed Quota to ResourceAggregate.

Updated client to use the new struct.

Testing Done:
Successfully ran:
gradle clean build  && ./pants src/test/python/apache/aurora/client:all
On a local scheduler tested /scheduler* and /quotas end points.

Will run end to end test tonight.

Bugs closed: AURORA-105

Reviewed at https://reviews.apache.org/r/18546/
Add support for slaveHosts set in TaskQuery.

Bugs closed: AURORA-232

Reviewed at https://reviews.apache.org/r/18526/
Added non-prod consumption info to getQuota call.

This call will be used by the role page in the UI.

Testing Done:
./gradlew clean build.

Bugs closed: AURORA-65

Reviewed at https://reviews.apache.org/r/17347/
Updated client to use the renamed getQuota API fields.

Testing Done:
./gradlew clean build.

Bugs closed: AURORA-65

Reviewed at https://reviews.apache.org/r/17347/
Remove LogStream.close, which was a no-op everywhere.

Reviewed at https://reviews.apache.org/r/18704/
Simplfiy TOC and anchors in remaining docs, among other niceties.

Reviewed at https://reviews.apache.org/r/18562/
Upgrade mesos to 0.17.0

Moves to using non-deprecated methods and calls the new mesos-log --initialize command before starting up the scheduler.

Testing Done:
./build-support/jenkins/build.sh
vagrant destroy -f
./src/test/sh/org/apache/aurora/e2e/test_end_to_end.sh
vagrant ssh devtools -c 'cd aurora; ./pants src/test/python/apache/aurora/executor:executor-large'

Bugs closed: AURORA-240

Reviewed at https://reviews.apache.org/r/18580/
AURORA-227: Aurora build should check for the Python version