update Moose support policy to reflect the current reality.
Merge pull request #70 from moose/perigrin/Clarify-Support

update Moose support policy to reflect the current reality.
changelog entry for Moose::Manual::Support update
for now, limit prereq checking to release time, to avoid tripping up travis (which does a build to get the full prereq list)
mark one leak test todo on 5.8
test with travis helpers
make sure we have modern EUMM for travis
parallel testing