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.
Fixed layout for some docs.
Minor changes to getting started page.
Updated home.md.
Fixed getting started page.
Updated getting started page to refer to 0.16.0.
Updated getting started page.