Small update to save UI/workspace settings

[EternaL]

I suggested this before, but I believe it's more than about time for a small update to save the UI/workspace settings. I use Spriter almost every work day, and setting up the UI the way I need it every time I open a scml is a huge hassle, when it could be so easily programmed. I recommend the ability to save and load named UI setups, or at the least just one UI saved automatically. To be specific, the UI/workspace includes:

• Canvas Background color
• Z-order menu scale (Ctrl+mouse wheel)
• Hierarchy menu scale
• Timeline Audio Playback setting
• Whether or not the Timeline options such as "only show selected" are checked or not
• Location and size of windows such as Object Properties, Palette, and Animations