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
Introducing Mesos modules.

Review: https://reviews.apache.org/r/25848
Replace EXPAND_AND_APPEND with BOOST_PP_CAT
Added ModuleManager::contains().
Sample isolator module copied from cgroups/cpu.

Review: https://reviews.apache.org/r/26071