Merge pull request #291 from est77/OSL_merge

OSL merge #3
removed unused code.
Merge branch 'master' of github.com:appleseedhq/appleseed
minor formatting fixes.
Fixed crash when rendering builtin projects
rendermanager.py 2.5: pings are now ordered from oldest to newest.
Merge branch 'master' into OSL_merge
rendermanager.py 2.6: simpler, more robust display of pings.
rendermanager.py 2.7: fixed crash when no pings are available.
Merge branch 'master' into OSL_merge
Made lambertianbrdf OSL friendly. Register closures.