make the truncate of step names to 50 chars
make the truncate of step names to 50 chars

with the new build page, its better to use maximum size for step names
tardyp/buildbot_travis,isotoma/buildbot_travis,tardyp/buildbot_travis,tardyp/buildbot_travis,isotoma/buildbot_travis,tardyp/buildbot_travis,buildbot/buildbot_travis,buildbot/buildbot_travis,buildbot/buildbot_travis