Change Aspect Switcher to use presetname instead of presetid

There's a problem when using Aspect Switcher with exported presets. Imagecache identifies presets differently depending on where it's stored:

• "Normal", non-exported presets: use the presetid
• "Default", exported presets: use the presetname
• Overridden presets: use the presetid

When you're telling Aspect Switcher to use a preset it will pick the identifier using the above rules. As a result, when you create the Aspect Switcher preset using either Normal or Overridden presets it uses the presetid, then when they're exported it can't find them anymore.

Instead of the above, Aspect Switcher should always use the presetname.