Fixed a style warning.
Modified two slave recovery tests to deal with the cases where 'update'
in an isolator launches a subprocess.

Review: https://reviews.apache.org/r/22900
Temporarily disabled health check tests due to MESOS-1533.
Properly disable health check tests.
Added support for following redirects to the fetcher (via stout/net).

I've added a call to set CURLOPT_FOLLOWLOCATION to true, which allows
the fetcher (when using http[s]://) to follow 30X redirects when
fetching.

Review: https://reviews.apache.org/r/22675
Explicitly terminated scheduler process in ~MesosSchedulerDriver().

Without this fix, Mesos tests that have assert failures get deadlocked
on ~MesosSchedulerDriver() (because driver.stop() is not called)
waiting forever for the scheduler process to exit. This causes the
tests to never exit.

Review: https://reviews.apache.org/r/22923
Added a test to verify that frameworks with equal share get equal
number of allocations.

Review: https://reviews.apache.org/r/22714
Wait on orphan cgroup destroy during launcher recovery.

Review: https://reviews.apache.org/r/22893
Fixed FrameworkReregistersFirst and SlaveReregistersFirst allocator tests.

Review: https://reviews.apache.org/r/22945
Fixed FaultToleranceTest.SlaveReregisterTerminatedExecutor test.

Review: https://reviews.apache.org/r/22947
Cleaned up libjvm to use DynamicLibrary.

Updated the code to leverage stout/dynamiclibrary.

Review: https://reviews.apache.org/r/21598
Refactored Subprocess to support execve style launch and customized
clone function.

Review: https://reviews.apache.org/r/22831
Updated mesos to adapt to the new Subprocess interfaces.

Review: https://reviews.apache.org/r/22851
Introduced a Subcommand abstraction in stout.

Review: https://reviews.apache.org/r/22764/
Added subcommand tests to stout tests.

Review: https://reviews.apache.org/r/22764
Reverted Operation in favor of using Subcommand.

Review: https://reviews.apache.org/r/22764
Refactored the mesos containerizer launcher to fix MESOS-1404.

Review: https://reviews.apache.org/r/22852
Handle container destroy during launch for MesosContainerizer.

Review: https://reviews.apache.org/r/22985
Added a network isolator based on port mapping.

Added a network isolator using port-range based traffic redirection on
Linux.

- Containers are assigned non-ephemeral ports by the scheduler and
  ephemeral ports by the network isolator.

- Virtual ethernet devices and traffic control filters are set up so
  that network traffic in and out of the containers is isolated based on
  the ports assigned to them.

- Containers run inside their own network namespaces with separate
  network stacks, from which per-container network statistics can be
  retrieved.

A joint work with:
- Cong Wang (cwang@twopensource.com)
- Jie Yu (yujie.jay@gmail.com)
- Ian Downes (ian.downes@gmail.com)

Review: https://reviews.apache.org/r/21594
Add some relation operators to os::Release

Review: https://reviews.apache.org/r/22897