when a project is passed on the command line on appleseed.studio, don't print the same error message twice if the project could not be loaded.
UI improvements, exposed more things.
Merge branch 'master' into blender_appleseed_addon
More UI improvements.
Merge pull request #248 from est77/blender_appleseed_addon

Blender appleseed addon work
in appleseed.studio, replaced the --final-render command line option by a --render option that takes the name of a render configuration in argument.  rendering no longer starts if no --render option is present.
Merge branch 'master' of github.com:jupiter-jazz/appleseed
updated and cleaned up the Python sample, added data directory.
formatting fixes.
updated copyright notice.