Updated documentation/flags regarding new default hostname semantics.

Review: https://reviews.apache.org/r/26185
Synced container network configurations with host network
configurations.

Review: https://reviews.apache.org/r/26197
Changed routing diagnosis socket state from enum to int so that they can
be bitwiseor'ed together.

Review: https://reviews.apache.org/r/26236
Included a missing header file in src/Makefile.am.
Fixed the flaky SlaveRecoverTest.MultipleSlaves.

Review: https://reviews.apache.org/r/26243
Switched path::join() to be variadic

Review: https://reviews.apache.org/r/25818
MESOS-1857 Fixed path::join() on older libstdc++ which lack back().

Review: https://reviews.apache.org/r/26256
Added webui_url to FrameworkInfo and web UI.

Allows frameworks to register a URL to its web UI.

Review: https://reviews.apache.org/r/26125
Replace some asserts with CHECKs in dispatch.

Review:
Added TCP RTT statistics for port mapping network isolator.

Review: https://reviews.apache.org/r/26090
Converted diagnosis socket Info to a struct.

Review: https://reviews.apache.org/r/26290
Moved Mesos version from mesos.hpp to version.hpp.

This allows the Module subsystem to simply include <mesos/version.hpp>
instead of inheriting the whole protobuf header chain.

Review: https://reviews.apache.org/r/26303
Install Python libraries during make install.

Because eggs are impossible to uninstall, pip + wheel has been added
as a packaging format. The wheels are generated in addition to eggs
and then subsequently installed/uninstalled.

Note that the building of eggs has not been removed. This is because
wheels cannot be run in place like eggs are via. modification of
PYTHONPATH. The eggs are needed for all the test scripts to run
correctly without actually installing anything locally.

Review: https://reviews.apache.org/r/24264
Split messages_launch_tasks into messages_launch_tasks and messages_decline_offers.

Review: https://reviews.apache.org/r/26329
Fixed ~Authenticator() to discard the promise.

Review: https://reviews.apache.org/r/26389
Fixed a resource accounting performance regression in the Master.

Review: https://reviews.apache.org/r/26392
Short term fix for MESOS-1866.

Review: https://reviews.apache.org/r/26400
First try to fix #1571. Propagate shutdown timeout to Executor and CommandExecutor via env variable. Remove escalation constant for command executor.
Second try to fix 1571.
Third try to fix 1571. Move shutdown adjust timeout logics into utility function, improve comments and style.