Fixed tests to not use cgroup isolators unless available and running
as root.

Review: https://reviews.apache.org/r/18023
Fixed tests to not use mlock on linux unless privileged.

Review: https://reviews.apache.org/r/18024
Fixed C++11 compilation error in mesos_containerizer.

Review: https://reviews.apache.org/r/18033
Fixed clang compilation errors in containerizer files.

Review: https://reviews.apache.org/r/18090
Fixed balloon framework script to use existing memory hierarchy.

Review: https://reviews.apache.org/r/18095
Patched glog to build for clang on Linux.

The patch is taken from:
https://code.google.com/p/google-glog/issues/detail?id=129

Review: https://reviews.apache.org/r/18096
Updated boost library to include files for interval set.
Used interval set to store holes and unlearned positions in replica.

Review: https://reviews.apache.org/r/18062
Updated logging levels for scheduler and executor drivers.

Review: https://reviews.apache.org/r/17964
Updated CHANGELOG for 0.18.0.
Updated configure.ac to 0.19.0.