Fixed omitted includes.

The includes of the respective C++11 standard headers were
missing. This issue becomes visible only when including one of those
headers before including a standard C++ header. As the namespace std::
simply does not exist without including a standard header, these two
headers produced errors on clang.

From: TILL TOENSHOFF <toenshoff@me.com>
Review: https://reviews.apache.org/r/16912
Added filtering to all tables.

From: Thomas Rampelberg <thomas@saunter.org>
Review: https://reviews.apache.org/r/16851
When the detectors fail, subsequent detect() calls now get failed
Futures directly.

From: Jiang Yan Xu <yan@jxu.me>
Review: https://reviews.apache.org/r/16586
Made ZooKeeperMasterContenderProcess::master an option to codify the
fact that it can be unset after construction.

From: Jiang Yan Xu <yan@jxu.me>
Review: https://reviews.apache.org/r/16588
ZooKeeperMasterContenderProcess::contend now checks if the future for
the previous contend() is still pending and if so it directly returns
that future without recontending.

From: Jiang Yan Xu <yan@jxu.me>
Review: https://reviews.apache.org/r/16589
LeaderContender::withdraw() now always returns false if there is no
membership to withdraw.

This includes when:
- withdraw() is called before contend()
- withdraw() is called after contend() but before the contender learns that it fails to obtain the candidacy
- withdraw() is called after the contender has learned that it had failed to obtain the candidacy

From: Jiang Yan Xu <yan@jxu.me>
Review: https://reviews.apache.org/r/16590
GroupProcess::abort() now also sets all owned memberships as cancelled.

From: Jiang Yan Xu <yan@jxu.me>
Review: https://reviews.apache.org/r/16591
Added an option to StartMaster() wait for leader election result before
returning.

From: Jiang Yan Xu <yan@jxu.me>
Review: https://reviews.apache.org/r/16742
Added marked.min.js directly into response of /help.

Review: https://reviews.apache.org/r/16933
Removed marked.min.js.

Review: https://reviews.apache.org/r/16934
Decoupled replicated log coordinator logic and made it asynchronous.

This is the first patch of a series of patches that implement a
catch-up mechanism for replicated log. See the following ticket for
more details: https://issues.apache.org/jira/browse/MESOS-736.

Here is a brief summary of this patch: (Sorry for the fact that we are
not able to break it into smaller patches :().

1) Pulled the original Coordinator logic out and divides it into
several Paxos phases (see src/log/consensus.hpp). Instead of using a
blocking semantics, we implemented all the logics asynchronously.

2) In order to ensure the liveness of a catch-uper, we implemented a
retry logic by bumping the proposal number. This also requires us to
slightly change the existing replica protocol.

3) Made the "fill" operation independent of the underlying
replica. Instead, introduced a catchup (see src/log/catchup.hpp)
function to make sure the underlying local replica has learned each
write.

4) Modified the log tests to adapt to the new semantics (see (3)
above).

This is a joint work with Yan Xu.

From: Jie Yu <yujie.jay@gmail.com>
Review: https://reviews.apache.org/r/14631
Libprocessify the coordinator.

From: Jie Yu <yujie.jay@gmail.com>
Review: https://reviews.apache.org/r/14902
Added log recovery support.

From: Jie Yu <yujie.jay@gmail.com>
Review: https://reviews.apache.org/r/15802
Refactored log tools and added a tool to initialize the log.

Also pulled storage related code out (I haven't changed them) from
replica.cpp.

From: Jie Yu <yujie.jay@gmail.com>
Review: https://reviews.apache.org/r/16433
Adjusted log tests to use the new log tool.

From: Jie Yu <yujie.jay@gmail.com>
Review: https://reviews.apache.org/r/16946
Added a watch function to watch for network size changes.

From: Jie Yu <yujie.jay@gmail.com>
Review: https://reviews.apache.org/r/16064
Only broadcast requests when there are enough replicas in the network.

From: Jie Yu <yujie.jay@gmail.com>
Review: https://reviews.apache.org/r/16065
Changed log recover implementation to only broadcast requests when
there are enough replicas in the network.

From: Jie Yu <yujie.jay@gmail.com>
Review: https://reviews.apache.org/r/16982
Added UNREACHABLE to stout.

Review: https://reviews.apache.org/r/16939
Used UNREACHABLE to silence a compiler warning.

Review: https://reviews.apache.org/r/16940