combine finalization_wait when combining tasks

Problem: combine_task and concat_task helpers lose the finalization_wait
information from all but the first task Resolution: use sum/max of
finialization_wait values in concat_task/combine_task

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

Reviewed at https://reviews.apache.org/r/24752/
AURORA-607:release script is broken

Updates release script to promote a voted on rc to an official release.

Testing Done:
./build-support/release/release -r 2

I have not tested the actual promotion of the rc to release, as this is the first official ASF release of Apache Aurora I saved that for Kevin to do

Steps to publish the 0.5.0 release with this script:
* git checkout 0.5.0-rc2
* apply this patch
* comment out dirty tree exit condition, line 89 of ./build-support/release/release
* test with: ./build-support/release/release -r 2
* rm -rf dist
* publish with: ./build-support/release/release -r 2 -p

Bugs closed: aurora-607

Reviewed at https://reviews.apache.org/r/24173/
Fix some bugs in the Update UI.

Reviewed at https://reviews.apache.org/r/25859/
Instrument task scheduling code to give visibility into failed searches and backoffs.

Reviewed at https://reviews.apache.org/r/25872/
Adding timing stats to DB stores.

Reviewed at https://reviews.apache.org/r/25897/
use javax.inject.Qualifier instead of @BindingAnnotation

See https://github.com/google/guice/wiki/JSR330

Testing Done:
./gradlew -Pq build

Reviewed at https://reviews.apache.org/r/25914/
HTML Grid Fixes in Scheduler UI.

Bugs closed: AURORA-436

Reviewed at https://reviews.apache.org/r/25913/
Disable updater by default in prod.

Bugs closed: AURORA-732

Reviewed at https://reviews.apache.org/r/25857/
Use AssistedInject to allow guice to construct StreamManager

Use Guice AssistedInject to construct StreamManager
Refactor other components in log to be Guice-constructed.

More info: https://github.com/google/guice/wiki/AssistedInject

Testing Done:
./gradlew -Pq build

Also manually verified that the annotated methods are exported in
vagrant (by using aurora_admin scheduler_snapshot devcluster and
looking at /vars)

Reviewed at https://reviews.apache.org/r/25870/
Improve aurora command-line help using metavars.

Bugs closed: aurora-737

Reviewed at https://reviews.apache.org/r/25918/
AURORA-736 - Update committer docs with steps for adding a gpg key

Bugs closed: AURORA-736

Reviewed at https://reviews.apache.org/r/25898/
Allow optional initial and desired states.

Bugs closed: AURORA-741

Reviewed at https://reviews.apache.org/r/25953/
Remove about plugin.

Reviewed at https://reviews.apache.org/r/25955/
Enable beta updater in example cluster.

Reviewed at https://reviews.apache.org/r/25958/
Prevent uncaught exceptions from straight up killing the executor.