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Removes out of date Hadoop on Mesos documentation from 2011.