updated copyright notices.
added foundation::StringLogTarget, a log target that outputs to a string.
added appleseed::shared::SuperLogger::set_log_target() and refactored the code accordingly.
default command line options (-h, -v etc.) are no longer automatically added.
on Windows, appleseed.studio displays the command line help in a message box since writing to the console from a Qt GUI application is impossible (or so it seems).
Merge branch 'master' of github.com:jupiter-jazz/appleseed
Merge branch 'master' into blender_appleseed_addon