MacGui: clean up headers and imports.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6661 b64f7644-9d1e-0410-96f1-a4d463321fa5
MacGui: do not redirect nil to the log.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6662 b64f7644-9d1e-0410-96f1-a4d463321fa5