Cleaned up some log and CHECK messages.

Review: https://reviews.apache.org/r/14135
Fixed broken build on GCC 4.8 due to -Wall.

With GCC 4.8, Boost fails to build from '-Wunused-local-typedefs', which
is implied by '-Wall'.

Review: https://reviews.apache.org/r/11974/
Updates Powered by Mesos list to include MediaCrossing and Xogito.
Updates Mesos Roadmap to point to JIRA.
Removes out of date Hadoop on Mesos documentation from 2011.
Merge branch 'master' into feature/Debian
OsTest fixed by MESOS-641