MacGui: Initial User Presets Implementation

MacGui: Initial User Presets Implementation
- Presets displayed in drawer in main window
- Presets stored in ~Libraries/Application Support/MediaFork/userpresets.plist
- Preference to show/hide presets drawer upon launch
- Confirmation window comes up when you delete a preset
Also added creation of x264profiles.plist in anticipation of x264 custom profiles

ToDo- Upcoming changes/additons:
- Alphabetize Presets List
- Change ugly button on main window to toggle drawer
- Specify a preset as default to set upon launch
- Deselect preset after it has been clicked
- Incorporate Picture settings into preset
- Pref on whether or not to alert upon Preset deletion
- Some more I can think of right now!

git-svn-id: svn://svn.handbrake.fr/HandBrake/branches/0.8.0_beta2_5.1@388 b64f7644-9d1e-0410-96f1-a4d463321fa5