hb_system_sleep: minor cleanup after last commit.



git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5337 b64f7644-9d1e-0410-96f1-a4d463321fa5
MacGui: improve hb_system_sleep support.



git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5338 b64f7644-9d1e-0410-96f1-a4d463321fa5
CLI: implement hb_system_sleep support.



git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5339 b64f7644-9d1e-0410-96f1-a4d463321fa5
hb_system_sleep: refactoring.

Also:

- release power	assertions before freeing them

- actually free	the power assertions in	  hb_close() (previously unused)



git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5340 b64f7644-9d1e-0410-96f1-a4d463321fa5