Fixed a warning in ReservationAllocatorTest.ResourcesReturned.

Review: https://reviews.apache.org/r/20633
Fixed a CHECK failure in Statistics.
Introduced exponential backoff for slave registration retries.

Review: https://reviews.apache.org/r/20502
Fixed a compiler warning in Statistics.
Cleanups in configure.ac for libjvm detection.

Late requests for cleanups in https://reviews.apache.org/r/19487.
Added a missing call to delete on the RegistrarProcess.
Renamed and moved MasterZooKeeperTest fixture.

Review: https://reviews.apache.org/r/20584
Integrated log storage into master.

Review: https://reviews.apache.org/r/20572/
Manipulated clock in metric tests to avoid rate limiting.

Review: https://reviews.apache.org/r/20642
Added message counters and a counter for slave timeouts during recovery in Master.

Review: https://reviews.apache.org/r/20638
Updated containerizer.proto's Launch message, added Destroy-, Wait- and Usage-messages.

Updated Launch message to reflect latest commits on the TaskInfo
related containerizer Launch call/s.  Added Destroy, Wait and Usage
messages to allow extending those messages in the future, where
needed.

Review: https://reviews.apache.org/r/20668
Introducing ContainerInfo as part of CommandInfo

Introduces the ContainerInfo protobuf as part of CommandInfo. Right
now, if present, the mesos containerizer fails the task launch to
point out that we do not support it on that containerizer.

This will be needed for the ExternalContainerizer and possibly other
containerizers as well.

Review: https://reviews.apache.org/r/20080
Refactored reading credentials out of master.cpp.

Review: https://reviews.apache.org/r/20301
Added a message string to the slave ShutdownMessage.

Review: https://reviews.apache.org/r/20302
Updated mesos-style.py with already-passing rules.

Review: https://reviews.apache.org/r/20649
Correct and simplify the ProcTests for threads.

Using clone() for creating threads is not advised because glibc expects
thread local storage to be set up in particular ways.

Review: https://reviews.apache.org/r/20632
Add a new boolean CommandInfo.URI.extract.

This is a patch that includes a new `extract` boolean value on
CommandInfo.URI to toggle the auto-extraction of compressed archives
when shipping URIs with an executor or task.

It's worth noting that this changes the behaviour of the
MESOS_EXECUTOR_URI environment variable used. I've added some comments
which outlines the expected format, instead of (e.g)
hdfs://foobar/testing.tar.gz+0 (1 signifying it's not executable)
there is now an extra flag on the end (X or N) defining whether to
auto-extract or not, resulting in hdfs://foobar/testing.tar.gz+0X by
default.

Review: https://reviews.apache.org/r/20674
Added authentication support for slaves.

Review: https://reviews.apache.org/r/18381
Use maven to compile and package Mesos' Java files.

Use Maven to build the Mesos jars, and include shaded protbuf jar. No
longer builds a custom protobuf jar but relies on Maven.

NOTE: If using the shaded jar then a JVM framework needs to update use
of the com.google.protobuf namespace to org.apache.mesos.protobuf.

Review: https://reviews.apache.org/r/20402
Updated policy for building against system dependencies.

Allows preventing the use of bundled libraries in favor of
preinstalled versions, where possible.

Using --disable-bundled generally switches from bundled to
preinstalled libraries.

If --disable-bundled is supplied or --with-leveldb[=DIR] was given but
the configuration phase could not locate the dependency, it stops with
an error.

If --disable-bundled is not supplied and no --with-leveldb[=DIR] was
given, the bundled library is built and used (DEFAULT).

NOTE:

1. This review only implements this preinstalled library usage on
LevelDB & ZooKeeper. Subsequent review requests for other bundled
libraries will follow as soon as this implementation has been
accepted.

2. This modification removed the old --without-installed-PACKAGE
semantics, as they conflict with well established --with-PACKAGE
semantics

Review: https://reviews.apache.org/r/20119