If a job is thrown out because of an error, print it to the standard error output

[eldruin]

If it is not possible to render a file, the error should be printed to the standard error output, not to verbose level 1.
This is important to an user that will see how a file is simply not rendered without any error message if there was a problem.

Regards,
Diego.

[eldruin]

Issue for this: http://www.synfig.org/issues/thebuggenie/synfig/issues/739

[morevnaproject]

Hello, Diego!
Thank you for the fix, it is merged now. ^__^
Please use "git rebase origin/master" in the future instead of "git merge origin/master". This will allow to avoid cluttered git history. Thank you!